underfloor heating...underfloor heating- a solution or a problem 3 heating system. this will lead to...

UNDERFLOOR HEATINGA solution or a problem?

Joakim Larsson

Master Thesis in Energy-efficient and Environmental BuildingsFaculty of Engineering | Lund University

Lund UniversityLund University, with eight faculties and a number of research centers and specialized institutes, is the largest establishment for research and higher education in Scandinavia. The main part of the University is situated in the small city of Lund which has about 112 000 inhabitants. A number of departments for research and education are, however, located in Malmö and Helsingborg. Lund University was founded in 1666 and has today a total staff of 6 000 employees and 47 000 students attending 280 degree programs and 2 300 subject courses offered by 63 departments.

Master Program in Energy-efficient and Environmental Building DesignThis international program provides knowledge, skills and competencies within the area of energy-efficient and environmental building design in cold climates. The goal is to train highly skilled professionals, who will significantly contribute to and influence the design, building or renovation of energy-efficient buildings, taking into consideration the architecture and environment, the inhabitants’ behavior and needs, their health and comfort as well as the overall economy.

The degree project is the final part of the master program leading to a Master of Science (120 credits) in Energy-efficient and Environmental Buildings.

Examiner: Hans Bagge (Building Physics)Supervisor: Dennis Johansson (HVAC)Keywords: Underfloor heating, Energy, Thermal mass, Energy efficiency, Heating systems

Thesis: EEBD–15/10

Underfloor heating- a solution or a problem

Table of content

1 Background ............................................................................................... 1

Energy and environmental issues 1 1.1

1.1.1 EU directives 1

1.1.1.1 National targets 1

1.1.2 Energy in Swedish residential buildings 1

Underfloor heating 2 1.2

1.2.1 Possible benefits of underfloor heating 2

1.2.2 Possible disadvantages with underfloor heating 2

1.2.3 Floor materials 3

1.2.4 System control 4

1.2.5 Underfloor heating in combination with heat pumps 4

Objectives 4 1.3

Limitations 4 1.4

2 Method ...................................................................................................... 7

Questionnaire study 7 2.1

Indoor climate measurements 8 2.2

2.2.1 Loggers and outdoor climate 8

2.2.2 Sorting of values 8

2.2.3 Analyses of the measured houses 9

Simulations 9 2.3

Industry knowledge and directives 9 2.4

3 Results and analysis ................................................................................ 11


3.1.1 Overall satisfaction 11

3.1.2 Discomforts 12

3.1.2.1 During heating season 13

3.1.2.2 During the whole year 13

3.1.3 Flooring materials 15

3.1.3.1 Cold floors 17

3.1.3.2 Varying temperature with different flooring materials 17

3.1.4 Wanted temperature 19



3.2.1 Temperature measurements 20

3.2.1.1 Distribution of logged temperatures 20

3.2.1.2 Influence of the outside temperature 25

3.2.1.3 Comparison between the two measured systems 26

3.2.2 Humidity measurements 27

3.2.2.1 Comparison between the two measured systems 33

3.2.2.2 Influence of the outside relative humidity 34

3.2.3 Analysing the measured residences 35

3.2.3.1 Comparing with the questionnaire answers 35

3.2.3.2 Moisture addition 36

Simulations 38 3.3

3.3.1 Energy simulations 39

3.3.2 Thermal mass 40

4 Discussion ............................................................................................... 43

Industry knowledge 43 4.1



Simulations 46 4.4

5 Conclusions ............................................................................................. 49

6 Future work ............................................................................................. 51

References ....................................................................................................... 54

Appendix A ..................................................................................................... 56

Appendix B ...................................................................................................... 57

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1 Background

Energy and environmental issues 1.1

According to the Intergovernmental Panel on Climate Change, IPCC, it is clear that humans

have had a grave impact on the climate changes that has taken place since the 1950s. The

atmosphere and the oceans are getting warmer which causes ice and snow to melt, raises the

sea-levels and increases the risk for natural disasters. The anthropogenic emissions of

greenhouse gases are at an all-time high, much because of the persistent use of fossil fuels.

80% of the world’s energy use still comes from fossil fuels. This might come as a surprise

since the negative impact of using fossil fuel is well known and that the environmental

question often is high on the political agenda. (IPCC,2013)

There are several reasons for this, one being the exponential increase of human population,

another is that although highly developed countries use of fossil fuel decreases the use in

less developed countries increases as they are reaching for quick and cheap changes.

Renewable energy sources, which have a much lower emission of greenhouse gases than

fossil fuels, are becoming more evolved and more common. This is a step in the right

direction, but it is not the only solution. In order to more effectively decrease the

environmental impact the use of energy should be lowered.

1.1.1 EU directives

In March 2007 the European Union leaders set new targets for its members in order to try

reducing the environmental impact and to support the development of renewable energy

sources. The three major objectives are; a 20% reduction in EU greenhouse gas emissions

from 1990 levels, raising the share of EU energy consumption produced from renewable

resources to 20 % and a 20% improvement in the EU’s energy efficiency. Because of these

three key objectives the targets are known as the “20-20-20” targets and are aimed to be

fulfilled in 2020.

1.1.1.1 National targets

The Effort Sharing Decision sets national targets for 2020 which is binding for each member

in the European Union. This decision targets the 60% of greenhouse gas emissions that is

not produced by the industrial sector and therefore not covered by the EU Emission Trading

System. The targets which is expressed in percentage-change from 2005s levels is decided

by the wealth of each country, this means that a wealthy country have to lower its emissions

more than a less wealthy. A less wealthy country is even allowed to increase their

percentage in order to leave space for a growing economy, the main goal is that in 2020 the

greenhouse gas emissions (covered by the Effort Sharing Decision) from all members of the

European Union should be lowered by 10%.

1.1.2 Energy in Swedish residential buildings

As set by the Effort Sharing Decision Sweden needs to lower its greenhouse emissions

outside the industrial sector with 17% compared to 2005s levels. Greenhouse gases from

residential buildings fall under this category and will be addressed by improving the energy

performance of buildings. (Council of European Union, 2015)


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In 2013 the energy consumed within residential buildings in Sweden was 63 427 GWh and

approximately 87% (55181 GWh) of this energy was used to heat the buildings. A good way

to reduce the consumption of energy and thereby lower the impact on the environment could

be to use more efficient heating methods. (Statistikcentralen, 2014)

Underfloor heating 1.2

Underfloor heating is often promoted to be an energy efficient heating method and is

becoming more and more common in Swedish single family houses. 61% of all single

family houses built in Sweden during 1996-2005 was equipped with underfloor heating,

which is a large increase compared to 1986-1995 where only 10% of new buildings where

equipped. (Betsi, 2009)

An underfloor heating system functions similar to the traditional radiator heating system,

but instead of having hot water running through and heating small surfaces, such as

radiators that are placed inside the room, the hot water runs through pipes that are casted in

the foundation under the floor or placed underneath the flooring material and therefore heats

up the larger floor area. According to the Swedish authorities the floor surface should not

exceed 27°C. (T2, 2002)

1.2.1 Possible benefits of underfloor heating

Underfloor heating should take away the factor of cold floors which is a desirable advantage

for many. It is also hidden underneath the flooring and does not take away space or affect

the appearance of the living area.

The human head thrives in a temperature of about 18-20°C but the feet wants a temperature

about 5°C higher than that. If a room is heated from the floor the general temperature in the

room should thereby be able to be lower, because the human feet is the primary sensory

organs for temperature i.e. if the feet are warm we feel warm. This should, according to

experts, allow for a room temperature that is 2-3°C lower and an energy saving of about

15% than if a conventional radiator system were used. (Boverket, 2015)

Since radiators are relatively small in area the water needs to be relatively hot in order to

heat an entire room, the radiated heat will also mostly be located around the radiator. This

should not be the case for underfloor heating. Since the entire floor is heated there is a lot of

contact between the heated floor and the air, which should allow for lower water

temperatures in the system and more dispersed heat in the entire room. (Boverket, 2015)

Utilizing the thermal storage in a building is often a good way to lower the amount of

energy needed to keep a building heated. Since the entire floor is heated when underfloor

heating systems are used there is a lot of mass where the thermal energy can be stored. This

stored energy should help to keep a uniform indoor temperature throughout the day and

lower the energy need.

1.2.2 Possible disadvantages with underfloor heating

Floor heating systems radiates the same amount of heat up to the building as it does down to

the foundation, it is therefore important to have a lot of insulation in the foundation to

prevent the energy from being wasted in to the ground. According to Swedish authorities

and experts it is recommended to have at least 250 millimetres of insulation below the floor


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heating system. This will lead to a higher initial cost of the system and can be hard to

implement when renovating or rebuilding. (Boverket, 2015)

It is also debatable that since such a large surface is heated by the system it is not to

recommend if the demand of energy is low. It will always take a certain amount of energy to

heat this large surface, which leads to that the minimum amount of energy that can be

provided by an underfloor heating system is higher than systems that uses smaller surfaces.

If the system is used in a well-insulated building with an energy demand that is lower than

the minimum energy that can be provided, the system may turn on and off and thereby

provide uneven temperatures and waste energy. This can make the underfloor heating

system difficult in new buildings where it is common to have a lot of insulation in order to

reach the energy goals.

Since it is common to have the floor heating casted inside the concrete, which can store a lot

of heat, there will be a time delay before any changes of heat supply will influence the

temperature of the room. This means that if the temperature outdoor rapidly changes it will

take time before the heating system adapts, which can lead to both overheated and cold

indoor climate. If the building has large windows and a slowly adapted heating system, solar

energy in combination with the stored energy in the concrete can rapidly increase the indoor

temperature and lead to uneven temperatures and overheating.

It is common to place radiators underneath windows to avoid downdraughts from the cold

window surfaces, which is not possible with an under floor heating system. To avoid this

complication the Swedish authorities and experts recommend that window constructions

with a U-value below 1.0 W/(m²K) are installed. These window constructions are expensive

and this will raise the price of installing underfloor heating both in new buildings and

renovations. (Boverket, 2015)

It can also be argued that there is an increased risk of water damage with a floor heating

system compared with other heating systems. If there is a leak in any of the water pipes in

the floor it would be hard to detect in time and the water damage it causes could be very

extensive. A discussion with Vattenskadecentrum (Water damage center) revealed no

known, apparent increase of such risks.

1.2.3 Floor materials

The type of flooring material chosen when using an underfloor heating system can have a

high impact on how the system works. If a heavy material, such as stone that stores a lot of

heat, is chosen it should create a system that takes a relatively long time to influence the

temperature in the room. When the outdoor temperature quickly drops this can help to keep

an even indoor temperature, but when the outdoor temperature quickly raises or the sun

starts to shine the combined energies could create overheating since the heating system is

slow to adapt. If a lighter material, such as parquet floor, that does not store so much heat, is

chosen the heating system should be quicker to adapt to changing conditions. If the outdoor

temperature then quickly raises or the sun starts shining the flooring material does not have

a lot of energy stored and will faster adapt. The same goes for if the temperature outside

rapidly drops.


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1.2.4 System control

There are different ways on how the underfloor heating can be controlled. The standard

being a thermostat either in the floor or in the room, this could create problems since heat

from other sources is not taken under consideration. There is a more energy efficient way

where the thermostat measures the temperature both in the floor and in the room at the same

time and thereby utilizes heat from other sources such as the sun or people. (T2, 2002)

1.2.5 Underfloor heating in combination with heat pumps

A heat pump can be used in combinations with an underfloor heating system. The efficiency

of the heat pump is called the Coefficient of Performance (COP) and is the ratio between the

energy usage of the compressor and amount of useful heat extracted from the condenser.

The COP for a heat pump is affected by several factors, one being the temperature

difference between the heat distribution and the heat source. The lower this temperature lift

is the higher the COP of the heat pump will be. See Figure 1.1 for example. (Berntsson,

2000)

Figure 1.1 COP difference with different temperature lifts with different types of heat pumps

Since an underfloor heating system operates with a lower temperature than for example a

radiator heating system the temperature lift will be lower when using this system, giving the

heat pump a higher COP. If a heat pump is used in combination with a heating system it is

therefore more beneficial to use an underfloor heating system.

Objectives 1.3

Underfloor heating has both advantages and disadvantages in different perspectives

regarding energy use, indoor climate and economy. Particularly the option to utilize the

thermal mass is influence with an underfloor heating system. This thesis will investigate the

existing knowledge on issue of underfloor heating and how residents with underfloor

heating perceive their indoor climate by a questionnaire. It will also include indoor climate

measurements and energy simulations to try to resolve important factors influencing the

energy use and indoor climate by use of underfloor heating.

Limitations 1.4

This thesis has limited its research to single family houses and thereby taking away the

factor of heating from others dwellings. Electric floor heating is not investigated in this

study, since it is considered having to high primary energy use to be worthwhile.

The underfloor heating system is only looked at as a heating system in this thesis and not as

a cooling system where cold water is run through instead of hot water.

TYPE OF HEAT PUMP 20°C 25°C 30°C 35°C 40°C 45°C 50°C 55°C 60°C

Earth source (G & W) 9.26 7.15 5.8 4.8 4.15 3.6 3.2 2.9 2.6

High efficiency ASHP 7.5 5.9 4.75 3.9 3.4 3 2.25 2 1.9

Standard ASHP 4.5 3.5 2.5 1.9 1.8 1.7 1.6 1.5 1.4

Variation of COP for different heat pumps with temperature liftLIFT (°C)


5

Measurements and simulations made in this study are limited to two heating systems, water

radiator heating systems and water underfloor heating systems.

Results from simulations are based on the geographical location Helsingborg in Sweden and

any conclusions based on these results may not be representative for different locations.


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2 Method

In this chapter the different methods used in order to fulfil the objectives of this thesis is

presented.

Questionnaire study 2.1

In order to determine how pleased residents are and how they perceive their indoor climate

with underfloor heating it was decided that a questionnaire study needed to be conducted. In

order to get sensible results the single family houses targeted in the study needs to fulfil

different requirements. The houses could not be too old since underfloor heating is rarer in

older buildings and building standards have changed. Row houses and multiple family

houses should be avoided because of the heat transfer between apartments or houses. If

possible the targeted houses should have the same outdoor climate and thereby be affected

by climate changes in the same way. It would also be preferred if the houses had different

types of heating system in order to compare the results.

It was, because of previous mentioned reasons, decided that to hand out paper

questionnaires directly to the houses would be the most efficient way to carry out the study.

By doing it this way, houses that did not meet the requirements could be skipped and only

information valuable to the study would be collected. A relatively new built residential area

with a lot of single family houses would fit well, both because of logistic reasons and that

the houses would share the same outdoor climate. The questionnaires were delivered with a

pre-stamped envelope and a covering letter (see Appendix A) that explains how and why the

study is conducted.

The questionnaire used is a composition between two surveys made by Boverket (small

houses and adult) and a series of made up questions that were relevant to this thesis. In order

to not reveal that the study is about underfloor heating or heating systems, which could

affect the residents’ answers, the headline of the questionnaire was “A few questions about

your indoor climate” and also contains some questions that are not relevant to the study. In

the survey (which can be seen in appendix B in Swedish) the residents answers questions on

a scale from either 1-5 or 1-3 on how pleased they are with aspects of their indoor climate

regarding different phenomenon, changing outdoor climate etc. The questionnaire also

contains questions about which types of flooring material the house has and which types of

heating systems that exists. The respondents will be able to remain anonymous or will be

able to fill in their name and phone number and thereby accepting further questioning if

needed.

The results from the questionnaire study will be analysed and answers from houses with

different heating systems will be compared, the level of satisfaction with underfloor heating

in different aspects will try to be determined and the most common floor materials will

affect the upcoming simulations in this thesis.

Maria Park, a residential area located a few kilometres north of Helsingborg in Sweden, was

chosen to be the target area of this study. It was chosen because it is a large residential area

(which means a lot of potential respondents), it is relatively new built and has a lot of single

family houses that does not have the same type of heating systems.


8

A total of 400 surveys were handed out directly to the mailbox of houses in Maria Park.

They were only handed out to buildings that looked to fit the requirements, houses that did

not were skipped.

Indoor climate measurements 2.2

In order to get a more detailed view of how the indoor climate changes with different

factors, it was decided that temperature and humidity measurements needs to be made on

single family houses with water underfloor heating systems and the more traditional water

radiator heating systems. Respondents from the questionnaire study with these types of

heating systems will be selected and asked if they allow for measuring in their homes. The

selected responders should meet the requirements mentioned in chapter 2.1. They should

especially share the same outdoor climate in order to be able to be compared with each

other.

The purpose of doing these measurements will be to try to see how and how fast the two

different systems adapts to changes in the outdoor climate, if the indoor temperature varies

more with one system compared to the other and if the average temperature with an

underfloor heating system is lower than with a radiator heating system.

In order to collect data when the outdoor climate creates interesting conditions and to be

sure that the heating systems would be turned on, the measuring period for all measured

houses was set to be between the 20th March and the 10

th of April (during the heating

season).

2.2.1 Loggers and outdoor climate

The loggers used in the measuring was Onset® HOBO® temp/RH loggers which has a

margin of error of ±0.21°C for temperature and a 2.5% accuracy for relative humidity. Since

±0.21°C does not make a significant difference in these measurements it was discussed and

decided that this should be ignored. The relative humidity was on the other hand corrected

since 2.5% makes a significant difference in the range of the data that was collected. The

logger registered values every fifth minute for both temperature and relative humidity.

(Onset, 2015)

The residents were instructed not to place the logger in direct sun light, on the floor or in a

box or cabinet. It was recommended to place the logger in the hall or living room where the

humidity from the kitchen or the bathroom affected as little as possible.

Data for the outdoor climate was taken from SMHI’s measurements of Helsingborg for the

time of interest. SMHI’s temperature and relative humidity measurements were given,

unlike the loggers, for every hour. (SMHI, 2015)

2.2.2 Sorting of values

Microsoft Excel was used to sort and analyse the measurements, all values was scanned in

order to detect unrealistic values that could have been caused by residents moving the

loggers. No such values were detected.

Since the measurements from SMHI was given every hour and the measurements from the

loggers every fifth minute the values did not enter the same rows in excel. This was

problematic because diagrams that include both measurements, in order to analyse the


9

results, were required. A macro was written in excel to insert eleven empty rows between

every value given from SMHI and thereby matching the loggers values. The macro can be

seen in Figure 2.1.

Figure 2.1 Macro used to insert eleven empty rows between every value in Excel

2.2.3 Analyses of the measured houses

In order to see how well the residents perceive their indoor climate, the answers of the

questionnaire study (for the measured houses) were compared with the measured data. To

give a clearer view on how the buildings are used, moisture supply were calculated for each

measured residences.

Simulations 2.3

Many of the possible advantages and disadvantages of having underfloor heating systems

comes from the fact that the system heats up a large area and then uses this stored energy to

create an even indoor climate throughout the day. It is also alleged that an underfloor

heating system allows for a lower room temperature and because of that needs less energy.

To try to determine if the possible advantages and disadvantages with an underfloor heating

system, which is more explained in chapter 1.2.1 and 1.2.2, is correct a series of simulations

will be made using Design Builder, which is an interface program for EnergyPlus.

The simulated building in this study will be a 16 m times 12 m one story single family

house. Two different heating systems will be used, water underfloor system and water

radiator system. Different flooring materials will be used based on the results from the

questionnaire study and different U-values on building components will be used in order to

try to see how this affects the energy consumption and balance of the systems.

Industry knowledge and directives 2.4

To be able to determine the possible advantages and disadvantages of using an underfloor

heating system and try to investigate the ones that cannot be investigated through

simulations, a literature study and interviews with expert and authorities will be conducted.

This study will also aim to find out the level of knowledge and what types of guidelines that

exist in the building industry.

The possible advantages and disadvantages found through this study are described in

chapter 1.1.2-1.2.2 and the conclusions of this study will be discussed in chapter 4.


10


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3 Results and analysis

In this chapter the results from the different studies are presented and analysed. Some

discoveries and interesting results are pointed out and shortly commented but will be more

discussed in chapter 4.


Off the 400 residents asked 141 responded, which is an answering rate of approximately

35%, most of them responding anonymously. 120 residences used underfloor heating and 21

used other heating systems.

The results of these 141 answered questionnaires were compared and analysed using

Microsoft Excel. In order to compare underfloor heating systems (shortened UFH) with

other systems, answered questionnaires with underfloor heating was sorted out, these results

was then compared with results from answered questionnaires with different heating system

(which is referred to in this thesis as “other”). In order to analyse the results, an average of

the answers is calculated and the percentile for 97.5% and 2.5% are used to see the spread of

the answers. The percentile is a measure that indicates the value where the given percentage

of observations in a group of observations is below, for example if the 97.5 percentile is 20,

97.5% of all values are below 20.

3.1.1 Overall satisfaction

The respondents have answered questions on how satisfied or dissatisfied they are with their

residence on a scale from 1-5, 1 being satisfied and 5 being dissatisfied. Underfloor heating

systems are compared with other heating systems in order to try to see if this system is more

satisfying.


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Figure 3.1 Results from the overall satisfaction questions in the survey. The higher the number on the x-

axis is the more dissatisfied the responders are.

In all questions seen in Figure 3.1 residences with underfloor heating is on average slightly

more satisfying than residences that use other heating systems. The spread in the answers

are however greater with underfloor heating system, this shows that responders that are

dissatisfied with energy use and thermal comfort of their residence are more dissatisfied if

they have an underfloor heating system. This is particularly evident regarding energy use.

High energy use on an underfloor heating system could indicate that the heat is wasted,

either by lack of insulation or by factors that forces the system to turn on and off in order to

keep the wanted indoor temperature. It could also mean that the residences with underfloor

heating systems do not have a lower indoor temperature than residences with other heating

methods.

3.1.2 Discomforts

The respondents answered questions on how often they experience different discomforts

such as draught or unsatisfying indoor temperatures. Answers were given on a scale from 1-

3, 3 being never, 2 being sometimes and 1 being often.

The goal of these questions was to try to see if different discomforts are more common or

less common when using an underfloor heating system and try to see if it is harder to control

these types of systems.

1.281.45

1.84 1.901.78 1.80

0

1

2

3

4

5

How satisfiedare you with

your residenceas a whole?

(UFH)


your residenceas a whole?

(Other)


your residenceregarding

energy use?(UFH)


your residenceregarding

energy use?(Other)

How satisfiedare you withthe thermalcomfort in

yourresidence?

(UFH)

How satisfiedare you withthe thermalcomfort in

yourresidence?

(Other)

Percentile 97.5

Average

Percentile 2.5


13

3.1.2.1 During heating season

Since the heating systems is mostly used during the heating season and since interesting

conditions are in place during this time some questions are asked only for this time frame.

The interesting conditions being that the solar energy is affecting the indoor climate even

though it is still cold outside. On the x-axis 3 means never, 2 means sometimes and 1 means

often.

Figure 3.2 Results of discomfort factors during the heating season

As seen in Figure 3.2 underfloor heating systems do not differ much from other systems

regarding discomfort during heating season. Interesting is that when the respondent have

problems with varying room temperatures they have more problem with underfloor heating

systems than other systems even though the average is better. Draught does not appear to be

more problematic in houses with underfloor heating and it is more common with high

temperatures when using other systems.

3.1.2.2 During the whole year

The respondents were then asked if and how frequent discomforting temperatures occur in

their residence during the summer and the winter.

2.73 2.80 2.66 2.45 2.43 2.35

0

1

2

3

4

Have you during the last 3 month (dec-feb) been troubled by....

Percentile 97.5

Average

Percentile 2.5


14

Figure 3.3 Survey results of discomforting indoor temperatures during summer and winter

The respondents view on discomforting temperatures during summer or winter in their

residence is almost the same whether they have an underfloor heating system or not (as seen

in Figure 3.3). The only difference is that underfloor heating systems have a slightly better

average when it comes to uncomfortable cold temperatures during winter time. Highest

discomfort is with high temperatures during summer time.

The responders were asked if and how often different types of draught occurred in their

residence and if and how often they experience cold floors. This is interesting since

underfloor heating systems does not prevent downdraught in the same way as for example

radiator heating systems.

Figure 3.4 Survey results on frequency of different discomforting factors

2.69 2.60 2.80 2.80 2.98 3.00

2.25 2.25

0

1

2

3

4

Are you in your residence troubled by...

Percentile97.5Average

Percentile 2.5

2.72 2.70 2.80 2.90 2.72 2.75

0

1

2

3

4


Percentile 97.5

Average

Percentile 2.5


15

As seen in Figure 3.4 downdraught from windows does not occur especially often in

residence with underfloor heating systems, which could be a possible disadvantage of using

this system, although it is more common than when using other systems. Another interesting

result is that cold floors is nearly as common in underfloor heating systems as it is in other

systems even though the heat radiates from the floor.

To try to see if underfloor heating systems are harder to control than other systems and if the

temperature varies during changes in the outdoor temperature, the respondents answered

questions on how they perceive these issues.

Figure 3.5 Results on how respondents perceive varying room temperatures and difficulty to influence the

this temperature

As seen in Figure 3.5 it is more common to have varying room temperature during

temperature changes outside when using an underfloor heating system. This indicates that

this system is slow to adapt to changing conditions. When the respondents have difficulty to

influence the room temperature they have a higher level of difficulty if they use an

underfloor heating system. Despite that it is more common to have a problem with this if

another system is used.

3.1.3 Flooring materials

To see which flooring material that is the most common when using underfloor heating

systems, the respondents answered questions on which types of flooring materials they have,

both on the ground floor and upstairs floors. It is also of interest to see if the designers of the

buildings prefer to use a flooring material that stores much heat or a material that stores

lower amounts of heat. These results are presented in percent of how many of the residences

that have a specific type of flooring material above an underfloor heating system.

2.29 2.55 2.50 2.25

0

1

2

3

4

varying roomtemperatures

duringtemperature

changes outside(UFH)

varying roomtemperatures

duringtemperature

changes outside(other)

difficulty toinfluence room

temperature(UFH)

difficulty toinfluence room

temperature(other)


Percentile 97.5

Average

Percentile 2.5


16

Figure 3.6 Results in percentage on how common certain flooring materials above underfloor heating is on

the ground floor

Figure 3.7 Results in percentage on how common certain flooring materials above underfloor heating is on

upstairs floors

From the results that is presented in Figure 3.6 and Figure 3.7 it is clear that wooden

flooring and tiled flooring, often in combination (which is the reason the percent’s adds up

to more than 100), is the most common flooring material when using underfloor heating

systems. These two flooring materials will therefore be used and analysed in the upcoming

simulations. It is approximately equally common with tiled as it is with wooden flooring and

therefore the results do not answer if a heavy flooring material is more preferred than a

lighter. The results also show that 70% of all respondents with underfloor heating systems

do not have underfloor heating systems on the upstairs floors. This can be explained by that

it takes a lot of labour to put in all the piping to have an underfloor heating system on

upstairs floors, which in turn can cost more than it gives.

2.5%

84.2% 85.8%

9.2%

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

PVC-/vinyl floor Wood/woodparquet

Tiled Stone

0.8%

14.2% 20.8%

1.7%

70.0%

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Carpeted Wood/woodparquet

Tiled Stone No underfloorheating upstairs


17

3.1.3.1 Cold floors

According to the survey residents with underfloor heating systems experience cold floors

nearly as much as residents without this system, which is peculiar since the heat is supplied

from the floor. In order to try to find a reason for this the surveys where cold floors were a

discomfort was sorted out to see which flooring material these houses have.

Figure 3.8 Flooring materials when having discomfort with cold floors and using an underfloor heating

system

As seen in Figure 3.8 it is most common to have a combination of tiled flooring and wooden

flooring. 82% of the houses in this study have that combination above their underfloor

heating system. It is therefore hard to be sure if one material causes cold floors more than

the other. It is only residents with these three flooring materials that have problems with

cold floors.

3.1.3.2 Varying temperature with different flooring materials

As explained in chapter 1.2.3 the flooring material can have an impact on how much the

indoor temperature varies with an underfloor heating system. In order to try to see if the

flooring material influences the varying indoor temperature, the respondents with this issue

was sorted out and the flooring materials of this residences was compared. This is done to

see if it is more or less common with varying indoor temperature with a lighter of heavier

flooring material.

90.9% 87.9%

3.0%

Wood/wood parquet

Tiled

Stone


18

Figure 3.9 Flooring material when having problems with varying indoor temperature caused by changing

outdoor temperature

As seen in Figure 3.9 it is slightly more common to have a heavy flooring material when

having problems with varying indoor temperature, the difference is although very small. In

order to investigate this further, only residence that often has problems with varying

temperature (answer 3) is sorted out and their flooring materials are compared.

Figure 3.10 Flooring material when often having problems with varying indoor temperature caused by

changing outdoor temperature

In Figure 3.10 the difference is clearer, it is more common with heavy flooring materials

when often having problem with varying indoor temperature caused by changing

temperature outdoors.

82.9%

2.7%

85.6%

9.9%

Wood/wood parquet

PVC-/vinyl floor

Tiled

Stone

75.0%

2.3%

84.1%

13.6%

Wood/wood parquet

PVC-/vinyl floor

Tiled

Stone


19

3.1.4 Wanted temperature

In the survey the respondents answered on which temperature they would like to have in

their residence and which temperature they experience, both for winter and summer. The

average difference between these temperatures would give a result on how close the heating

system is on giving the wanted temperatures, at least how close the respondents perceive it

to be.

Figure 3.11 Results on the difference between wanted and perceived indoor temperature in winter and

summer

As seen in Figure 3.11 the difference in wanted and perceived indoor temperature is very

low during winter time. In summer the difference is, in both underfloor heating and other

systems, much larger but more when using underfloor heating. Some of the respondents

using this system could even perceive temperatures more than 9°C warmer than what they

would like to have.


In the questionnaire study the respondents could leave their name and telephone number and

accept to be contacted if needed. Some respondents did that and a few of them was

contacted and asked if they would allow temperature and humidity measuring in their

residence. Three residences with water radiator systems and four residences with water

underfloor heating systems allowed measuring.

0.07

-1.94

0.15

-1.75

-10

-9

-8

-7

-6

-5

-4

-3

-2

-1

0

1

2

3

Winter (UFH) Summer (UFH) Winter (other) Summer (other)

Temperature difference/°C

Percentile97.5

Average

Percentile2.5


20

3.2.1 Temperature measurements

One of the possible advantages of underfloor heating is that it should allow a lower indoor

temperature than for example radiator heating systems. In order to see if this is correct, in

the measurements made for this study, an average of all logged temperatures in each

residence was calculated and compared.

Figure 3.12 Results of the average temperatures of the measured residences

As seen in Figure 3.12 only “Underfloor heating 2” has a significantly lower average

temperature than the residences using radiators. In the other residences the average

temperature is fairly even. The percentiles give an indication that the spread of logged

temperatures is larger in the residences that uses underfloor heating systems.

3.2.1.1 Distribution of logged temperatures

To take a closer look on the spread and to some extent see how much the indoor temperature

varies, the logged temperatures were sorted from smallest to largest and then compared.


21

Figure 3.13 Variation in temperature for the measured residences

In Figure 3.13 it can be seen that the radiator systems (the line of Radiator 1 is underneath

the line of Radiator 2) has a spread that is more even than the underfloor heating systems.

The temperature in all residences seems to more or less follow the curve of the outdoor

temperature. The underfloor heating systems have more thermal spikes, which could

indicate that these systems are slower to adapt to raising outdoor temperatures or solar

gains.

To try to see how fast the heating system in each residence adapted to changing outdoor

temperatures, the measured indoor temperature was compared with the outdoor temperature.

Looking for heat peaks indoors and if they occur shortly after raising temperatures outside,

also to try to see how high these peaks gets. In figure 3.14-3.20 this comparison is presented

for each residence.

Figure 3.14 Inside temperature for Radiator 1 compared with the outside temperature

-10

-5

0

5

10

15

15

16

17

18

19

20

21

22

23

24

25

26

0 1000 2000 3000 4000 5000 6000

Temperature/°C Temperature/°C

Radiator 1

Radiator 2

Radiator 3

Underfloor heating 1




Outdoors (secondaxis)

-10

-5

0

5

10

15

20

22.5

23

23.5

24

24.5

25

25.5

19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00


InsideTemp

OutsideTemp


22



Figure 3.17 Inside temperature for Underfloor heating 1 compared with the outside temperature

-10

-5

0

5

10

15

20

22.5

23

23.5

24

24.5

25

25.5

19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00


Insidetemp

OutsideTemp

-10

-5

0

5

10

15

20

19

19.5

20

20.5

21

21.5

22

22.5

23

23.5

24

19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00


InsideTemp

OutsideTemp

-10

-5

0

5

10

15

20

21

21.5

22

22.5

23

23.5

24

24.5

25

25.5

26

19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00


InsideTemp

Outsidetemp


23




-10

-5

0

5

10

15

20

18

19

20

21

22

23

24

19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00


InsideTemp

OutsideTemp

-10

-5

0

5

10

15

20

21

21.5

22

22.5

23

23.5

24

24.5

25

25.5

26

19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00


InsideTemp

OutsideTemp

-10

-5

0

5

10

15

20

19

20

21

22

23

24

25

19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00


InsideTemp

OutsideTemp


24

It is no surprise that the temperature raises shortly after raising temperatures outside, the

interesting, with the comparisons in Figure 3.14-Figure 3.20, is to see how fast the system

adjusts its heating after these heat peaks outside. After examining these diagrams and the

data behind them it seems that the underfloor heating systems is slower to adapt and

therefore causes higher temperature peaks than radiator systems. To more see how the

temperature differs inside the measured residences the difference between the maximum and

the minimum temperature in each residence was calculated.

Table 3.1 The temperature difference between the maximum and the minimum temperature for every

measured day in the measured residences

Date UFH1/°C UFH2/°C UFH3/°C UFH4/°C Rad1/°C Rad2/°C Rad3/°C

20/03/2015 1.34 0.81 0.96 2.20 0.51 0.46 0.77

21/03/2015 0.86 0.62 0.69 0.76 0.82 1.03 1.01

22/03/2015 2.02 1.43 1.05 2.10 0.87 0.91 1.03

23/03/2015 1.82 1.00 1.51 2.27 0.79 0.38 1.08

24/03/2015 0.77 0.62 0.65 3.31 1.04 0.26 0.96

25/03/2015 0.41 0.40 0.45 3.70 0.91 0.29 0.57

26/03/2015 0.60 0.79 0.41 1.72 1.01 0.22 0.57

27/03/2015 1.37 0.93 0.93 1.89 0.96 0.58 0.88

28/03/2015 1.70 0.74 1.17 2.54 0.98 0.34 0.93

29/03/2015 1.41 0.74 0.62 1.75 1.35 0.22 1.17

30/03/2015 0.96 0.90 1.32 2.89 1.28 0.67 3.39

31/03/2015 0.81 1.12 0.72 0.65 1.11 0.24 1.24

01/04/2015 1.75 0.79 1.58 2.13 1.28 0.41 1.27

02/04/2015 2.86 1.55 1.65 2.09 0.94 0.50 1.27

03/04/2015 2.52 4.63 1.58 2.62 1.15 0.74 1.15

04/04/2015 2.47 2.19 1.73 2.81 1.08 0.77 1.41

05/04/2015 2.67 1.43 3.37 2.43 0.70 1.04 1.55

06/04/2015 3.59 2.05 1.42 2.98 2.07 2.00 2.01

07/04/2015 1.39 1.00 0.84 1.58 1.71 0.24 1.08

08/04/2015 1.71 2.02 1.82 3.05 1.49 0.67 1.15

09/04/2015 1.66 1.55 2.35 3.48 1.28 0.53 1.44

Average: 1.65 1.30 1.28 2.33 1.11 0.60 1.23


25

As seen in Table 3.1 it is more common to a have larger temperature difference between the

daily maximum and minimum indoor temperatures when using an underfloor heating

system. When examining Figure 3.18 it looks like Underfloor heating 2 should have a less

varying indoor temperature than the rest of the residences but it has a peak on the third of

April that affects its average in Table 3.1. If this date was to be taken away the average daily

temperature difference would be 1.13°C, which is as good as for a residences using radiator

heating.

3.2.1.2 Influence of the outside temperature

In order to closer investigate how much the outside temperature influences the inside

temperature, diagrams with the indoor temperature as a function of the outside temperature

were made. With the help of Excel a trend line and an equation that shows the connection

between the two variables were added.

Figure 3.21 The inside temperature as a function of the outside temperature in Underfloor heating 1

As seen in Figure 3.21 there is, unsurprisingly, a connection between the outdoor and indoor

temperature. The interesting being the factor in front of x (for future references called k) in

the equation, the closer this factor k is to one the larger the connection is between the

outside and inside temperature. The coefficient of determination (R²) describes how well

one variable describes the other, in this case how well the outdoor temperature describes the

indoor. If R² is between minus one and zero the connection is negative, if it is zero there is

no connection and if it is between zero and one the connection is positive. This analysis was

made for all measured residences and the resulting coefficients are presented in the table

below.

y = 0.1054x + 22.526 R² = 0.1947

21.5

22

22.5

23

23.5

24

24.5

25

25.5

26

-10 -5 0 5 10 15 20

Temperature/°C

Temperature/°C


26

Table 3.2 The connection variables for the indoor and outdoor temperatures in the measured residences

k R² Average

k

Average

R²

Underfloor heating 1 0.1054 0.1947

0.0842

0.1128




Radiator 1 0.0286 0.0399

0.0300

0.0833 Radiator 2 0.0145 0.0195

Radiator3 0.0467 0.1904

It seems like the outdoor temperature has a slightly larger influence on the indoor

temperature when using underfloor heating systems. The average coefficients k and R² are

larger for the residences with underfloor heating systems.

3.2.1.3 Comparison between the two measured systems

In order to see how the two different systems compare with each other, interesting values

such as average temperature, maximum and minimum temperature, for the measured

temperatures of all residences with underfloor heating was compared with the values of all

residences with radiator heating systems.

Table 3.3 Temperature comparisons between the two systems

Underfloor heating Radiators

Average temperature/°C 21.81 23.35

Standard deviation/°C 1.556 0.459

Maximum temperature/°C 25.525 25.113

Percentile 95/°C 24.026 24.120

Percentile 75/°C 22.848 23.597

Percentile 50/°C 22.178 23.328

Percentile 25/°C 20.674 23.117

Percentile 5/°C 19.08 22.853

Minimum temperature/°C 18.604 21.036

The standard deviation is a distribution measurement on how the values are distributed

around the average value. As seen in Table 3.3 the average temperature is lower in the

residences with underfloor heating but the standard deviations is larger, which indicates that

temperatures when using this system varies more.


27

3.2.2 Humidity measurements

In order to see if there is any differences in humidity levels when using underfloor heating

systems or radiator heating systems the same comparisons made with temperature in chapter

3.2.3 was made for the measured humidity.

Figure 3.22 Results of the average relative humidity in the measured residences

In Figure 3.22 it is showed that there is no significant difference in the average relative

humidity levels when using underfloor or radiator heating systems. The spread of the levels

differs a lot from residence to residence and will therefore be further investigated.

To try to see if there is more spread in relative humidity levels with the different heating

systems, the measured values was sorted from smallest to largest and then compared.

35.44 35.8136.54

31.22

37.79

34.87

38.40

25

30

35

40

45

50

Radiator 1 Radiator 2 Radiator 3 Underfloorheating 1

Underfloorheating 2

Underfloorheating 3

Underfloorheating 4

Relative humidity/%

97.5 percentile

Average

2.5 percentile


28

Figure 3.23 Variation in relative humidity for the measured residences

Figure 3.23 show that the residences using radiator heating systems have more high values

of relative humidity, the residences with underfloor heating have more even relative

humidity levels.

To try to see how the relative humidity changes with the indoor temperature, these values

were compared and analysed. This should give an indication of when the high level of

relative humidity occurs.

Figure 3.24 Indoor relative humidity for Radiator 1 compared with the indoor temperature

40

50

60

70

80

90

100

20

25

30

35

40

45

50

55

60

0 2000 4000 6000

Relative humidity/%

Relative humidity/%

Radiator 1

Radiator 2

Radiator3

Underfloorheating 1Underfloorheating 2Underfloorheating 3Underfloorheating 4Outside(second axis)

25

30

35

40

45

50

22.5

23

23.5

24

24.5

25

25.5

19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00

Relative humidity/%

Temperature/°C

Indoortemp

IndoorRH


29



Figure 3.27 Indoor relative humidity for Underfloor heating 1 compared with the indoor temperature

20

30

40

50

22.5

23

23.5

24

24.5

25

25.5

19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00

Relative humidity/%

Temperature/°C

Indoortemp

IndoorRH

20

25

30

35

40

45

50

55

19

19.5

20

20.5

21

21.5

22

22.5

23

23.5

24

19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00

Relative humidity/%

Temperature/°C

Indoortemp

IndoorRH

20

30

40

21

21.5

22

22.5

23

23.5

24

24.5

25

25.5

26

19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00

Relative humidity/%

Temperature/°C

Indoortemp

IndoorRH


30




30

40

50

18

19

20

21

22

23

24

19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00

Relative humidity/%

Temperature/°C

Indoortemp

IndoorRH

25

30

35

40

45

21

21.5

22

22.5

23

23.5

24

24.5

25

25.5

26

19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00

Relative humidity/%

Temperature/°C

Indoortemp

IndoorRH

20

25

30

35

40

45

50

55

19

20

21

22

23

24

25

19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00

Relative humidity/%

Temperature/°C

Indoortemp

IndoorRH


31

The relative humidity is the amount of humidity (in g/m³) in the air divided by the amount

of humidity the air can carry (in g/m³) and the higher temperature of the air, the more

humidity it can carry. This should, if no other factors influences mean that if the indoor

temperature increases the relative humidity should decrease. As seen in Figure 3.24-Figure

3.30 this is the case on some occasions but not all the time, which than means that there is

other factors influencing the indoor relative humidity. Since the indoor temperature affects

the indoor relative humidity it can be seen that residences with a more even temperature has

a more even relative humidity. The peaks and drops in relative humidity often appear with

changes in the temperature.

Another factor that can affect the indoor relative humidity is the outdoor relative humidity,

in order to see how this affects these two relative humidity’s was compared.

Figure 3.31 Relative humidity for Radiator 1 compared with the outdoor relative humidity


40

50

60

70

80

90

100

20

25

30

35

40

45

50

19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00

Relative humidity/%

Relative humidity/%

IndoorRH

OutdoorRH

40

50

60

70

80

90

100

20

25

30

35

40

45

50

19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00

Relative humidity/%

Relative humidity/%

IndoorRH

OutdoorRH


32


Figure 3.34 Relative humidity for Underfloor heating 1 compared with the outdoor relative humidity


40

50

60

70

80

90

100

20

25

30

35

40

45

50

55

60

19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00

Relative humidity/%

Relative humidity/%

IndoorRH

OutdoorRH

40

50

60

70

80

90

100

20

22

24

26

28

30

32

34

36

38

40

19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00

Relative humidity/%

Relative humidity/%

IndoorRH

OutdoorRH

40

50

60

70

80

90

100

3032343638404244464850

19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00

Relative humidity/%

Relative humidity/%

IndoorRH

OutdoorRH


33



As seen in Figure 3.31-Figure 3.37 the indoor relative humidity curve mostly follows the

curve of the outdoor relative humidity in all residences, with an even difference. In some

cases the relative humidity indoors is high even through the outdoors relative humidity is

relatively low, this could be due to the presence of people, which produce both heat and

moisture.

3.2.2.1 Comparison between the two measured systems

In order to see how the two different systems compare with each other, interesting values

such as average humidity, maximum and minimum humidity, for the measured temperatures

of all residences with underfloor heating was compared with the values of all residences

with radiator heating systems.

40

50

60

70

80

90

100

25

30

35

40

45

50

19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00

Relative humidity/%

Relative humidity/%

IndoorRH

OutdoorRH

40

50

60

70

80

90

100

20

25

30

35

40

45

50

55

60

19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00

Relative humidity/%

Relative humidity/%

IndoorRH

OutdoorRH


34

Table 3.4 Relative humidity comparisons between the two systems

Underfloor heating Radiators

Average relative humidity/% 35.57 35.93

Standard deviation 4.29 3.59

Maximum relative humidity/% 51.85 55.83

Percentile 95 43.16 41.57





Minimum relative humidity/% 24.54 21.66

As seen in Table 3.4 the relative humidity does not differ much between the two systems.

Which type of heating system that is used probably does not affect the indoor relative

humidity as much as other factors does, for example the outdoor relative humidity.

3.2.2.2 Influence of the outside relative humidity

In order to see how much the outside relative humidity influences the indoor, the same

comparison that was made for temperature in chapter 3.2.1.2 was made for the relative

humidity.

As seen in Table 3.5 there is a clear connection between the outdoor and indoor relative

humidity. It does not seem to matter which heating system that is used, there is probably

other factors in the building that influences this more.


35

Table 3.5 The connection variables for the indoor and outdoor relative humidity in the measured

residences

k R² Average

k

Average

R² Underfloor heating 1 0.0487 0.0608

0.0932

0.1359 Underfloor heating 2 0.0525 0.043



Radiator 1 0.0881 0.1005

0.1057

0.1314 Radiator 2 0.0819 0.1091

Radiator3 0.1471 0.1845

3.2.3 Analysing the measured residences

In order to see how well the responders perceive their indoor climate the questionnaire

answers for the measured residences was compared with the measured data. The added

excess moisture was also calculated to try to see how these measured residences were used

during the measuring period.

3.2.3.1 Comparing with the questionnaire answers

Since humans produce both heat and moisture it is interesting to see if and how much the

amount of residents influences the temperature and relative humidity. It is also interesting to

see how accurate the responders are with their perceived temperature and how close the real

temperature is to the wanted.

Table 3.6 Number of residents, the perceived and wanted temperature of the responders compared with

the average temperature and relative humidity in the measured residences

Residents Average

temperature

(°C)

Average relative

humidity (%)

Perceived temperature

during winter (°C)

Wanted

temperature

during

winter (°C) RAD1 2 23.50 35.44 21 21

RAD2 4 23.33 35.81 20 20

RAD3 3 22.03 36.54 22 24

UFH1 2 23.00 31.22 21 21

UFH2 4 19.49 37.79 20 20

UFH3 4 22.41 34.87 20 20

UFH4 5 22.34 38.40 23 23


36

As seen in Table 3.6 it is not safe to say that more residents will lead to higher average

temperature or relative humidity, even if this would be logical. There are many other factors

that influence these results, such as size of the house and ventilation. The perceived

temperature in the residences is often lower than the measured averages, the exceptions

being UFH2 and UFH4.

Figure 3.38 Questionnaire study answers from the measured residences. The scale on the y-axis describes

how often discomforts occur, 3 being never and 1 being often.

As seen in Figure 3.38 the residents in the measured residences do not experience high

levels of discomforts during the heating season, with the exception of UFH4, which matches

the results from the measurements.

3.2.3.2 Moisture supply

In order to calculate the moisture supply for the measured buildings the following formulas

were used:

(1) 𝑣 = 4.7815706 + 0.34597292 ∙ 𝑡 + 0.0099365776 ∙ 𝑡2 +

0.00015612096 ∙ 𝑡3 + 1.9830825 ∙ 10−6 ∙ 𝑡4 + 1.5773396 ∙ 10−8 ∙ 𝑡5

𝑣 = 𝑠𝑎𝑡𝑢𝑟𝑎𝑡𝑖𝑜𝑛 𝑣𝑎𝑝𝑜𝑟 𝑐𝑜𝑛𝑡𝑒𝑛𝑡/(𝑔/𝑚3)

𝑡 = 𝑠𝑎𝑡𝑢𝑟𝑎𝑡𝑖𝑜𝑛 𝑡𝑒𝑚𝑝𝑒𝑟𝑎𝑡𝑢𝑟𝑒 𝑖𝑛 ℃

(2) 𝑣𝑖 = (𝑟/100) ∙ 𝑣

𝑟 = 𝑟𝑒𝑙𝑎𝑡𝑖𝑣𝑒 ℎ𝑢𝑚𝑖𝑑𝑖𝑡𝑦/(%)

𝑣𝑖 = 𝑣𝑎𝑝𝑜𝑟 𝑐𝑜𝑛𝑡𝑒𝑛𝑡 𝑖𝑛𝑑𝑜𝑜𝑟/(𝑔/𝑚3)

0

1

2

3

Hightemperaturesduring heating

season

Varyingtemperaturesduring heating

season

Too cold duringwinter

Too hot duringwinter

Varyingtemperature withchanging outdoor

temperature

Difficulty to affectthe temperature

RAD1

RAD2

RAD3

UFH1

UFH2

UFH3

UFH4


37

(3) 𝑚 = 𝑣𝑖 − 𝑣𝑜

𝑚 = 𝑚𝑜𝑖𝑠𝑡𝑢𝑟𝑒 𝑠𝑢𝑝𝑝𝑙𝑦/(𝑔/𝑚3)

𝑣𝑜 = 𝑣𝑎𝑝𝑜𝑟 𝑐𝑜𝑛𝑡𝑒𝑛𝑡 𝑜𝑢𝑡𝑑𝑜𝑜𝑟/(𝑔/𝑚3)

The average moisture supply for the measured residences during the measured time period

is presented in Table 3.7. As seen there is no significant difference between the two systems

moisture supply averages, but the underfloor heating system seems to vary more between

the different houses.

Table 3.7 Average moisture addition for the measured residences during the measured period

Radiator 1 6.12 g/m³

Radiator 2 6.12 g/m³

Radiator3 5.73 g/m³

Underfloor heating 1 5.05 g/m³




Radiator average 5.99 g/m³

Underfloor heating

average

5.47 g/m³

In Figure 3.39 the distribution of the moisture addition are presented. Again it could be said

that the residences using underfloor heating varies more from each other than the residences

using radiator systems. This again is an indication that installing and using underfloor

heating systems correctly seems to be harder than for radiator systems.


38

Figure 3.39 The distribution of the moisture supply in the measured houses.

Simulations 3.3

To try to see if the energy use in a single family house is lower when using underfloor

heating systems than when using radiator heating systems, how the floor material affects the

energy use and if the thermal storage is more optimised with underfloor heating a series of

simulations was conducted.

Since wood/wood parquet and tiled flooring was the most common materials in the

questionnaire study these materials was used in the simulations. In order to see if there is a

difference between the two systems when having a good insulated building or a bad

insulated building simulations was done for both. The buildings simulated are identical, only

interesting parameters was chanced and these are presented in Table 3.3.8

Table 3.3.8 The different properties of the simulated buildings

Good building Bad building

Wall U-value/ (W/(m²K)) 0.1 0.35

Roof U-value/ (W/(m²K)) 0.1 0.25

Slab insulation U-value

(W/(m²K))

0.149 0.238

Slab insulation thickness/

(mm)

250 141

Windows U-value/ (W/m²) 0.774 1.987

0

2

4

6

8

10

12

20/03/2015 00:00 10/04/2015 00:00

v/(g/m³)

Radiator 1

Radiator 2

Radiator3






39

Well-insulated buildings are (in the diagrams) shortened with Good, bad insulated buildings

are shortened by Bad. Radiator systems are shortened with RAD and underfloor heating

systems with UFH.

3.3.1 Energy simulations

To see if the energy used to heat a single family house is lower when using underfloor

heating systems than radiator heating systems energy simulations was made with the two

different heating systems and two different flooring materials. A possible advantage of the

underfloor heating system is that it allows for a lower indoor temperature, therefore the

simulations was made for 16°C, 18°C, 20°C, 22°C and 24°C indoor temperature.

Figure 3.40 Simulated annual energy use for a good insulated single family house with different heating

systems and flooring materials

In Figure 3.40 the energy needed to heat a well-insulated single family house to different

temperatures, with different heating methods and different flooring materials over one year

is shown. Underfloor heating with tiles as flooring material is always the most energy

efficient heating system, regardless on the indoor temperature. Radiators with tiled flooring

use less energy than underfloor heating with wood/wood parquet this could be because of

the larger thermal storage capacity of the tiled flooring.

50

70

90

110

130

150

170

190

16°C 18°C 20°C 22°C 24°C

Energy/ (kWh/year/m²)

Good UFH Wood

Good RAD Wood

Good UFH Tiles

Good RAD Tiles


40

Figure 3.41 Simulated annual energy use for a bad insulated single family house with different heating

systems and flooring materials

In Figure 3.41 the energy needed to heat a badly insulated single family house to different

temperatures, with different heating methods and different flooring materials over one year

is shown. Although the slab has little insulation the underfloor heating system is more

energy efficient than the radiator system, even if the radiator system uses tiled flooring and

the underfloor heating system uses wood/wood parquet.

3.3.2 Thermal mass

In order to see how big of an impact the thermal mass has on the two systems, energy

simulations with different thickness (to represent thermal storage) on the flooring material

was made. This was done to try to see if underfloor heating systems use the thermal mass of

the floor better than radiator systems.

Because the tiled flooring had the lowest energy use this material was used in the

simulations and since the indoor temperature is not relevant for the results of the thermal

mass an indoor temperature of 20°C was used.

50

70

90

110

130

150

170

190

210

230

250

16°C 18°C 20°C 22°C 24°C

Energy/ (kWh/year/m²)

Bad UFH Wood

Bad RAD Wood

Bad UFH Tiles

Bad RAD Tiles


41

Figure 3.42 Results for energy use with different flooring thicknesses in a well-insulated house

It clearly shows in Figure 3.42 that the yearly energy needed to heat the building gets lower

the more thermal storage that is available in the floor. Since the house with underfloor

heating already has lower energy use it is hard to see if this system utilizes the thermal mass

better than a radiator system. To try to find this out a second comparison was made, where

the energy needed for 20mm flooring material were subtracted from the other thicknesses.

This allows too see how well the different systems utilize added thermal storage, regardless

from the difference in energy use.

Figure 3.43 Differences in energy use with different flooring thicknesses in a well-insulated house

As Figure 3.43 illustrates there is a difference in how well the systems utilizes thermal mass

in the floor, the underfloor heating system takes slightly more advantage of the added mass

than the radiator system.

To see if amount of insulation has an impact on the above presented results the same

comparisons was made for a house that is badly insulated. The interesting point being that

more heat can be lost through the foundation.

24700

24800

24900

25000

25100

25200

25300

25400

25500

20mm 30mm 40mm 50mm 100mm

Energy/(kWh/ year)

Good UFH Tiles

Good RAD Tiles

41

79

113

242

37

71

104

223

0

50

100

150

200

250

300

30mm 40mm 50mm 100mm

Energy/(kWh/ year)

Good UFH Tiles

Good RAD Tiles


42

Figure 3.44 Results for energy use with different flooring thicknesses in a badly-insulated house

Figure 3.45 Differences in energy use with different flooring thicknesses in a badly-insulated house

Figure 3.44 and Figure 3.45 matches the previous results with that the underfloor heating

system benefits more from added thermal storage in the floor than the radiator system. The

difference between the two systems ability to utilize the thermal mass is however smaller

with a badly-insulated house.

28000

28500

29000

29500

30000

30500

31000

20mm 30mm 40mm 50mm 100mm

Energy/(kWh/ year)

Bad UFH Tiles

Bad RAD Tiles

30

58

88

197

29

57

84

190

0

50

100

150

200

250

30mm 40mm 50mm 100mm

Energy/(kWh/ year)

Bad UFH Tiles

Bad RAD Tiles


43

4 Discussion

Industry knowledge 4.1

The knowledge on how to use and install an underfloor heating system in the building

industry seems to be quite good but it might not be as well-known as one would like. In any

case it is not hard to find information on the subject. On the other hand this information

often comes from manufacturers of the system and of course makes the underfloor heating

system look like the ideal heating method.

The Swedish Energy Agency, the Swedish Consumer Agency, the National Housing Board

and Formas have in collaboration created a writing called “Grundtips för golvvärme”

(Boverket, 2015) (Basic tips for underfloor heating) and in this writing it is stated what you

should look out for when installing this kind of system. They recommend that 250

millimeters of insulation is used underneath the floor heating and states that the goal of

using underfloor heating is to lower the indoor temperature. To lower the indoor

temperature is according to this writing a prerequisite in order to save energy. Anyone who

wants to install or have underfloor heating systems can easily obtain this information but

one can only hope that they do.

The possible advantages and disadvantages found through the literature study and

interviews with experts on the subject can be seen in chapter 1.2.1 and 1.2.2. One possible

disadvantage is that since such a large area is heated there could be a risk that the system

would overheat. It would thereby not be suited for use in for example passive houses that

are well-insulated. In order for this to be true the underfloor heating systems needs to be

applied underneath the entire floor or at least most of it. It has through this study come to

the writers’ knowledge that passive houses with underfloor heating systems are being build,

where only the floor area close to the walls are fitted with underfloor heating. This allows

for a smaller area to be heated and should prevent the system from overheating. How well

this works is still not known to the author of this thesis but it is regardless an attempt to

address this disadvantage.


Figure 3.1 does not show that, even with the advantages of the hidden underfloor heating

system, residences with this system are more satisfied than residences with other heating

methods. A reason for that can be found in the same figure. If a resident is dissatisfied from

a thermal comfort point of view, it is more so if using underfloor heating. The same goes for

the respondents’ perception of their residence energy use. This raises the suspicion that if an

underfloor heating system is not installed or used correctly it could be a bad choice. With

that said the respondents using underfloor heating is on average just as satisfied with the

thermal comfort and energy use as respondents with other systems. This can be interpreted

as if an underfloor heating system is installed and used correctly it is at least as satisficing as

other systems regarding thermal comfort and energy use and more satisfying as a whole.

The most important when investigating heating systems is to investigate how it works

during the heating season. Since this is the time of year when the system is in operation, the

solar gains can affect the indoor climate even if it is still cold outside and draught occur


44

more distinctly during this period. In the questionnaire study the respondents were asked if

they had perceived problems with draught, too high room temperatures or varying room

temperatures during December to February. To have discomforting high temperatures is on

average less common with underfloor heating systems during this period, if too high

temperatures occur it is also more frequent when using other systems. If the respondents

were troubled by varying room temperature it is more frequent with underfloor heating

systems during this period but more common to occur if another system is used.

Draught from windows in buildings using underfloor heating systems is not more common

than when using other systems, this might be surprising since underfloor heating does not

prevent draught. The answer probably lies in that the residences investigated in this study

was relatively new and was equipped with good windows that prevents downdraught. At

least the study proves that if you have an underfloor heating system you do not necessarily

have problems with downdraught.

A risk of using an underfloor heating system was that it is more common to overheat and

create high indoor temperatures than other systems. This does not seem to be the case, at

least not in this study. It is actually perceived more common with overheating during the

heating season with other heating methods. On the other hand the respondents with

underfloor heating perceive to a more varying room temperatures. As mentioned before

underfloor heating can have problems adjusting to changing conditions since there is a lot of

stored heat in the foundation, this is slightly more true if the residence have a heavy flooring

material, as shown in chapter 3.1.3.2. Another reason could be how the system is controlled.

If the system is not controlled with an energy efficient thermostat and only measure the

temperature in the floor it will not be able to adapt quick enough if the indoor temperature

rises. The ability to influence the room temperature is on average perceived to be easier with

underfloor heating but if it is perceived to be hard it is harder with this system. This could

also be explained by not using energy efficient thermostats.

It is more common than not that if the respondent is dissatisfied the respondent is more

dissatisfied if they use underfloor heating systems. This could be because this system

requires more from the rest of the building, it is also a newer system and it seems like the

knowledge in the industry and of the residents is not as well-known as for example more

traditional heating systems. Therefore it could be that this lack of knowledge leads to badly

installed systems that are not in harmony with the rest of the building. Despite that it seems

that it is more common that the underfloor heating system is installed and used correctly and

that the residents with this system is on average more pleased than residents with other

systems.

An interesting result from the questionnaire study was that residents with underfloor heating

experience cold floors just as much as residents with other systems despite the fact that the

heat is supplied from the floor. One way to explain this could be that it is more common

with flooring materials that is perceived to be colder such as stone or tiles when having an

underfloor heating system. As shown in chapter 3.1.3.1 it is hard to prove that this would be

the reason since wooden flooring and tilled flooring is equally common. Another way to

explain this could be with the fact that residents that have underfloor heating expect their

floors to be warmer than residents with other systems. If the system then is turned off,

because the indoor temperature is satisfying, the residents could be more displeased with the

temperature of the floor since they expect it to be warmer.


45

It is absolutely most common with tiled or wooden flooring when using underfloor heating,

which shows that the fact of using insulating materials like carpeting above the system is

well-known to be a bad idea. Since tiled and wooden flooring is equally common it is

difficult to say which material that is preferred by the designers of the residences. It could

also be hard to control the choice of flooring material since it has a big impact on the

appearance of the room.

The difference between the perceived temperatures and the wanted temperatures is during

winter very small regardless of which system that is being used. Despite that the

respondents with underfloor heating experience less discomforting low temperatures during

this period. Since this probably is the most important aspect of a heating system it is a good

result for the underfloor heating system. In summer the difference is much higher in all

systems, that this should have anything to do with which heating system the respondents

have is unlikely. Hopefully the heating system is turned off during summer.

It seems that underfloor heating systems if used and installed correctly is in most cases more

satisfying than other heating systems.


It is claimed by authorities that lowering the indoor temperature is required in order to save

energy with an underfloor heating system. It is therefore interesting that in the measured

houses it is only one (Underfloor heating 2) out of four residences with underfloor heating

that has an average temperature which is significantly lower than for the once using radiator

systems. This would then mean that the three other residences with underfloor heating use

more energy than the once using radiator systems. It could be that the residence with the low

temperatures is the only measured residence with a properly working underfloor heating

system. It could also be that the residents in the three other houses does not know how to

control the heating system or believes/wants the indoor air temperature should/to be this

high. Either way it is a result that speaks against the use of underfloor heating systems. On

the other hand measurements should be performed in more houses to ensure this finding.

The ability for the different systems to adapt to changing conditions is worse with the

underfloor heating systems than it is with radiator systems with exception of Underfloor

heating 2. Even if this residence has on one occasion a very high peak in temperature (which

could have been caused by uncontrollable circumstances) it has the steadiest temperatures of

the measured residences. It is the complete difference with Underfloor heating 4 where the

indoor temperature varies very much even though it is the same kind of system. This

indicates that the comfort provided by an underfloor heating system can vary very much

depending on the residence and/or the residents. Changes in indoor temperature mostly

occurs quickly after changes in the outdoor temperature, the houses with radiator systems

adapts faster and stops heating quicker than the underfloor heating systems. This can be

because of the thermal storage in the foundation which is more used when using underfloor

heating systems and creates a more uneven temperature and higher peaks in the indoor

temperatures. Neither system seems to have problems when the outdoor temperature drops.

One could think that the underfloor heating system should control drops in the outdoor

temperature better because of the thermal storage even if this does not show in the measured

indoor temperatures. It could be that the radiators is faster to detect the falling temperatures


46

and therefore starts heating faster than the underfloor heating system, it would then use

more energy but keeps the temperature steady.

The average relative humidity of the measured residences does not differ much when using

underfloor heating systems or radiator systems, the exception being Underfloor heating 1

which has a lower average than the rest of the residences. It is surprising that Underfloor

heating 2 do not have a higher average relative humidity since it also has lower average

temperature and that the air therefore can carry less moisture. The reason for this could be

that there is less residents in this house, which leads to less moisture and heat production. It

could also be that this house and heating system is better built and/or controlled than the

others and therefore perform better. The latter probably being the most likely one. Even if

their lives less people or not in this residence it is adapted for the situation and is an

indication that underfloor heating systems can have a lower indoor temperature that is

steady and probably need less energy than radiator heating systems. As seen in the results of

the humidity measurements the outdoor relative humidity has a higher impact on the indoor

humidity than the indoor temperature does. When the indoor temperature rises it is common

in the measurements that the relative humidity does too, which as previously explained

means that there is another factor involved. The presence of people is probably that factor.

Using underfloor or radiator heating systems does not seem to affect the indoor relative

humidity significantly, at least they do not affect it in different ways. There are probably

other aspects in the building construction that affect the indoor relative humidity levels

more.

Simulations 4.4

According to information gathered in the literature study it is required to lower the indoor

temperature in order to decrease the energy use when using underfloor heating systems. As

seen in simulation results in chapter 3.3.1 this is not the case when comparing underfloor

heating with radiator systems, even if the indoor temperature is set on 24°C the underfloor

heating system has a lower annual energy need than the radiator system. As stated in chapter

1.2.1 underfloor heating systems should allow an indoor temperature 2-3°C lower than when

using a radiator system. That would then mean that if a radiator system has a heating set

point on 22°C the underfloor system should allow 20°C.


47

Figure 4.1 Difference in annual energy use for radiator (22°C) and underfloor heating (20°C)

When comparing the annual energy use of these cases there is (as shown in Figure 4.1) a

grave difference between the two systems. According to the results from Design builder the

underfloor heating system would only need 87% for a well-insulated house and about 81%

for a badly-insulated house of the energy that is needed for the radiator system. This result

speaks against the belief that underfloor heating systems would not be suited for well-

insulated houses and implies that this system is energy efficient. It seems like, according to

Design builder, that underfloor heating is a superior heating method in all conditions that

was tested in this study. Results from simulations does not necessary reflect the reality and

there is of course a chance that Design builder is exaggerating the impact of underfloor

heating systems. Another aspect could be that in the simulations the underfloor heating

system works and is used as intended, which may not be the case in real houses. The human

factor seems to have a big impact on how well the heating systems work and it seems like

the knowledge on how to control an underfloor heating system is not as well-known as for

other heating systems. As seen in Figure 3.5 residents that have problems influencing the

heating systems have more problems when using an underfloor heating system. It could be

that this kind of systems is harder to control since there are more factors that can influence

the control of the system. It could also be that it, compared to other systems, requires more

knowledge to install correctly and that this knowledge is not always known by the workers

installing it. Since it is on average (according to the respondents) easier to influence the

room temperature with underfloor heating systems it seems like the latter explanation is the

most correct one.

When it comes to the utilization of thermal mass the underfloor heating systems seems to be

better than the radiator system, this is no surprise since underfloor heating heats a larger

volume of potential heat storage. It does not seem like the indoor temperature drops or

varies more because of lack of thermal storage with an radiator system, this can be

explained by that radiator systems is quick to adapt to changing conditions and therefore

starts heating to avoid changing indoor temperature. This does that the radiator systems

3325 3431

6644 6787

0

1000

2000

3000

4000

5000

6000

7000

8000

Well-insulatedwith wooden

flooring

Well-insulatedwith tilled flooring

Badly-insulatedwith wodden

flooring

Badly-insulatedwith tilled flooring

Energy difference/(kW

h/year)


48

needs more energy compared to an underfloor heating system (as seen in chapter 3.3.2). The

difference in the ability to utilize the thermal storage between the two systems is lower with

a badly-insulated house. This is because the stored heat escapes through the foundation and

that the underfloor heating systems’ radiated heat can be wasted the same way.

It is not tested in this thesis how the different systems would perform if there is zero

insulation in the foundation since this hopefully would not be the case in reality.

If using a heat pump in combination with the heating system it is possible to lower the

energy need of the system. It is even more efficient if using underfloor heating since the

temperature lift is lower with this system, which leads to a higher COP on the heat pump.


49

5 Conclusions

Residents with underfloor heating systems are on average more pleased with the

energy use, the thermal comfort and their residence as a whole compared with

residents with other heating methods.

Discomforting high temperatures and varying temperatures is perceived to be less

common during the heating season with underfloor heating systems than other

systems. Draught is perceived to be slightly more common during this time period.

It is perceived that too cold temperatures during the winter period occur more

often when not using underfloor heating. The perceived temperature during

winter when using an underfloor heating system is very close to the wanted

temperature.

Varying room temperatures during temperature changes outside is perceived to be

common with underfloor heating, the reason for this is the utilization of thermal

mass which creates a delay before the system stops heating the room. Despite that

it is perceived to be easier to influence the room temperature when using this

system compared to others.

Wood/wood parquet and tiled flooring is the most common flooring materials

when using underfloor heating. Residents with heavy flooring materials that store

a lot of heat have more often problems with varying indoor temperatures.

An underfloor heating system can lower the indoor temperature and thereby have

a lower energy need than other systems. For this to be true the system has to be

installed and controlled properly, which is not always the case.

Residences with underfloor heating systems have a more varying indoor

temperature than residences with radiator heating systems, according to the

measuring study in this thesis.

Changing outdoor temperatures have a greater influence on the indoor

temperature when using underfloor heating systems compared to radiator heating

systems.

The utilization of thermal storage helps to lower the energy need when using

underfloor heating system during the heating season. This system also utilizes

added thermal storage better than radiator systems.


50


51

6 Future work

In order to see if the conclusions in this thesis are accurate it would be interesting

to see questionnaire studies and measurements from other locations.

More research on heating systems in combination with heat pumps or solar

collectors would be interesting to see, since this could change which systems that

is the more energy efficient.

Different energy supplies could influence the energy efficiency of the system,

testing this would therefore be important.

Since the main heating systems in this thesis were underfloor heating and radiator

systems it could be interesting to see comparisons with other systems.

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Appendix A

Hej!

Det ställs mer och mer krav på framtidens bostäder. Man tar fram nya metoder för att

värma upp våra bostäder och få ner energianvändningen så mycket som möjligt. Det är

viktigt att detta sker på ett sätt där bostadens inomhusklimat inte påverkas negativt.

För att kunna förbättra framtidens bostäder behövs mer information om hur de boende

upplever sitt inomhusklimat. Därför skickar nu Lunds Tekniska Högskola ut denna enkät till

Er med syftet att undersöka vad ni tycker om er bostads inomhusklimat. Era svar kommer

att användas som grund till framtida arbete med utveckling av energieffektivva

uppvärmningsmetoder.

Era svar är mycket värdefulla för vårt arbete med att utveckla framtidens bostäder!

Stort tack för hjälpen!

Student Avdelningsföreståndare

Joakim Larsson, Ing. Dennis Johansson,TeknDr.

Appendix B

1. Hur många personer bor i bostaden?

Räkna med alla vuxna och barn som bor i bostaden minst hälften av tiden.

1 □ Vuxna (18 år och äldre)...... personer

2 □ Barn 13-17 år .................... personer

3 □ Barn 0-12 år ....................... personer

2. a) Vilket är husets ungefärliga byggnadsår?

År

b) Vilken typ av hus är det?

1 Radhus

2 Kedjehus

3 Parhus

4 Fristående villa

5 Annat

c) Hur många våningsplan ovan mark har huset?

1 1

2 1 ½

3 2 eller fler

d) Hur är det huvudsakligen grundlagt?

1 Betongplatta på mark

2 Torpargrund/krypgrund/plintgrund

3 Källare/souterräng

4 Vet ej

3. Är du nöjd med din bostad som helhet?

1. □ Nöjd 2. □ Ganska nöjd 3. □ Varken/eller 4. □ Ganska missnöjd 5. □ Missnöjd

4. Hur nöjd eller missnöjd är du med bostaden vad gäller.....

Nöjd Ganska nöjd Varken/eller Ganska missnöjd Missnöjd

A Storlek? □ □ □ □ □

B Planlösning? □ □ □ □ □

C Dagsljus? □ □ □ □ □

D Trivsel? □ □ □ □ □

E Bostadskostnad? □ □ □ □ □

F Energiförbrukning? □ □ □ □ □ 5. Har du de senaste 3 månaderna känt dig besvärad av någon eller några av följande

faktorer i din bostad?

Ja ofta (varje vecka) Ja ibland Nej aldrig

A Drag □ □ □

B För hög rumstemperatur □ □ □

C Varierande rumstemperatur □ □ □

D Instängd (”dålig”) luft □ □ □

E Torr luft □ □ □

F Obehaglig lukt □ □ □

6. Hur tycker du att värmekomforten i stort sett är i din bostad?

Mycket bra Bra Acceptabel Dålig Mycket dålig

1.□ 2.□ 3.□ 4.□ 5.□ 7. Besväras du av att du i bostaden har...

Ja ofta (varje vecka) Ja ibland Nej aldrig

A alltför kallt på vinterhalvåret? □ □ □

B alltför varmt på vinterhalvåret? □ □ □

C alltför kallt på sommarhalvåret? □ □ □

D alltför varmt på sommarhalvåret? □ □ □

E kalla golv? □ □ □

F drag från fönster? □ □ □

G drag från ytterdörr? □ □ □ H varierande rumstemperaturer vi d

temperaturväxlingar utomhus? □ □ □

I svårigheter att påverka rumstemperaturen? □ □ □ 8. Vilken typ av uppvärmning finns huvudsakligen på bostadens bottenvåning?

1. □ Vattenburen radiatorvärme 5. □ Golvvärme - vattenburen

2. □ El-radiatorer – äldre typ 6. □ Golvvärme - el

3. □ Elradiatorer – oljefyllda 7. □ Annat

4. □ Luftvärme, dvs varmluft cirkulerar i huset 8. □ Vet ej

9. Vilken typ av uppvärmning finns huvudsakligen på bostadens ovanvåning?




4. □ Luftvärme, dvs varmluft cirkulerar i huset 8. □ Vet ej 8. □ Har ingen

ovanvåning

10. Vilken typ av uppvärmning finns i bostadens våtrum?




4. □ Luftvärme, dvs varmluft cirkulerar i huset 8. □ Vet ej

11. Om det finns golvvärme på bostadens bottenplan, vilket golvmaterial ligger ovan det?

1 Linoleum

2 PVC-/plastmatta

3 Heltäckningsmatta

4 Plastlaminat

5 Trä/träparkett

6 Klinker

7 Sten

8 Annat material

9 Har ej värmegolv

12. Om det finns golvvärme på bostadens övreplan, vilket golvmaterial ligger ovan det?

1 Linoleum

2 PVC-/plastmatta


4 Plastlaminat

5 Trä/träparkett

6 Klinker

7 Sten

8 Annat material

9 Har ej värmegolv

13. Finns fönsterventiler i sovrum/vardagsrum?

1 Ja

2 Nej

14. Hur sker tillförseln av värme till huset?

1 Fjärrvärme/central värmepanna för området

2 Värmepanna i huset

3 Annan

4 Vet ej

15. a) Hur ofta vädras det vanligtvis under uppvärmningssäsongen (d.v.s. september-

april)?

1 Dagligen/nästan varje dag

2 Ungefär 1 gång i veckan

3 Någon gång i månaden

4 Vädrar sällan eller aldrig

b) När det vädras, sker det oftast genom att …

1 ...ha vädringsfönster/fönster öppet hela dagen/natten

2 ...ha vädringsfönster/fönster öppet några timmar

3 ...ha korsdrag några minuter

4 Vädrar aldrig

16. a) Har nytt golv lagts in i bostaden under de senaste 12 månaderna?

1 Ja

2 Nej

b) Vilken typ av golvmaterial finns i bostaden?

Flera alternativ kan anges.

1 Linoleum

2 PVC-/plastmatta


4 Plastlaminat

5 Trä/träparkett

6 Klinker

7 Sten

6 Annat

17. Hur varmt är det ungefär i bostaden under ....

Vinterhalvåret? Sommarhalvåret?

°C °C 18. Vilken temperatur skulle ni vilja ha i bostaden under...

Vinterhalvåret? Sommarhalvåret?

°C °C

19. Om vi har fler frågor angående ert inneklimat hade det varit bra om vi kunde komma i kontakt med er, ber er därför fylla i kontaktuppgifter nedan (om ni absolut inte vill bli kontaktade så bortse från att fylla i).

Namn: .............................................................................. Telefonnummer:..........................................................

Dept of Architecture and Built Environment: Division of Energy and Building DesignDept of Building and Environmental Technology: Divisions of Building Physics and Building Services

underfloor heating...underfloor heating- a solution or a problem 3 heating system. this will lead to...

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