energy consumption in mid-and high-rise residential buildings

Energy Consumption in Mid- and High-rise Residential Buildings

The Myths and Realities of Real Building Energy Performance

Warren Knowles P.Eng.

January 19, 2011

Understanding of:

Learning Objectives

Energy consumption trends within new and older high-rise buildings (where energy is used / can be conserved).

Impacts of design of the building enclosure on energy consumption.consumption.

Relationship between enclosure air-tightness, suite compartmentalization, and ventilation strategies on energy consumption.

How simple calibrated energy modeling can be used to assist with the design.

How to comply with current energy code requirements including ASHRAE 90.1.

How to improve performance characteristics of building enclosure assemblies.

By 2020:

33 % reduction in Greenhouse Gas Emissions

Energy Efficient Building Strategy

BC Climate Action Plan

-20% energy use per household

Clean Energy Act

2020 Goals:

Carbon Neutral New Buildings

20% Reduction in Energy Consumption and Greenhouse Gas Emissions in Existing Buildings

City of Vancouver – Greenest City Action Plan

Buildings account for 55% of Greenhouse Gas EmissionsBuildings account for 55% of Greenhouse Gas Emissions

How will we get there?

Absolute Energy Intensity requirements (kwh/m2/yr)

Incentives and other means

Multi-Unit High-Rise Residential Building Energy Study

Energy consumption of over 60 mid- to high-rise Multi-Unit Residential Buildings (MURBs)

Constructed between 1974 and 2002

Half of study buildings underwent a full-scale building enclosure rehabilitation

Allows for the assessment of actual energy

CMHC SCHL

Allows for the assessment of actual energy savings from enclosure performance

Pre- and post-rehabilitation R-values, air-tightness characteristics are compared to energy consumption.

Other building performance characteristics as a result of the enclosure improvements are assessed.

Energy Units

Typical energy intensity units - kWh/m2/yr or GJ/m2/yr in Canada

Gas is metered/billed in units of GJ, and electricity in units of kWh

Both energy intensities are used in the study

1 kWh = 10 x 100 watt lights bulbs – 1 hour

1 kJ = Burning a match

1 GJ = 277.8 kWh (or ekWh) 1 GJ = 277.8 kWh (or ekWh)

Why High-rise MURBs?

55% of GHGs from Buildings in Vancouver

High-rise MURBs largest emitters (COV)

Not well understood

Study Buildings

39 mid and high rise residential buildings

4,400 residential suites

4,600,000 square feet of floor area

Study Buildings

$5,000,000 annual energy costs

44,000,000 kWh annual electricity use

173,000 GJ annual gas use

Design Characteristics – Older Buildings

Lower glazing percentage

Framed walls

Exposed concrete

Punched windows

Design Characteristics – 1990s Buildings

Higher glazing percentage

Concrete walls

Framed wall

Window wall and punched windows

High glazing percentage

Metal panel cladding

Concrete fins

Window wall / spandrel panels

Design Characteristics - More Recent Buildings

Top down:

Annual bulk energy billed known

Suggests good overview

Problems:

Metering varies (individual for electrical, vs. common for gas)

Building features and activities

Top-down vs. Bottom-up Analysis

Building features and activities

• Pools, elevators, fireplaces, lighting, etc.

Seasonal conversion efficiencies not known

Bottom-up:

Detailed information available

Can identify anomalies or errors in billing data

One building at a time

Building systems known

Modeling software available

Better weather data (smart metering data during cold rain events)

Occupant Behavior?

Monthly Energy Consumption – Typical Building

kWh

Baseline Suite Electricity – No Space Heat

Baseline Gas – No Space Heat

Estimated Monthly Heating

kWh

Energy Intensity kWh/m2/yr

200

250

300

350Common Electricity

Suite Electricity

Gas

Average = 213 kWh/m2/yr

Median = 217 kWh/m2/yr

Std Dev = 42 kWh/m2/yr

Range = 144 to 299 kWh/m2/yr

Average = 213 kWh/m2/yr

-

50

100

150

200

81

14

4 95

24

26

16

31

8 76

21

22

61

93

33

22

04

52

91

74

36

03

12

8 61

4 33

9 25

73

04

12

4 14

05

92

13

65

8

Distribution of Space Heat Energy

% of Total Building Energy Used for Space Heat% of Total Building Energy Used for Space Heat% of Total Building Energy Used for Space Heat% of Total Building Energy Used for Space Heat

40%

50%

60%

% Total Energy Which is Heat

Electrical Heat

Gas Heat

Average 37% of total building energy is

used for heat

Of this portion an average of 69% of

this energy is from gas

Average of 37% of Energy is used for Space-Heating

0%

10%

20%

30%

26 18 11 6 157 2 743 21

32 61

52 14 2459 44 17 29 42

4030 3141

202862 45

60 33 19 36 58 12 39 3 863 9

Building ID

% Total Energy Which is Heat

Energy Consumption vs Year of Construction

200

250

300

350

Energ

y C

onsu

mpti

on - k

Wh

/m2/y

r

Total Energy

Space Heat Energy

-

50

100

150

200

19

72

19

74

19

76

19

78

19

80

19

82

19

84

19

86

19

88

19

90

19

92

19

94

19

96

19

98

20

00

20

02

20

04

Year of Construction

Energ

y C

onsu

mpti

on - k

Wh

/m

Fuel for Space Heat versus Age of Building

100

120

140

160

Gas MAU or Fireplace Space Heat

Electric Resistance Space Heat

Electric Space Heat Trend

Gas Space Heat Trend

kWh/m2/yr

-

20

40

60

80

19

74

19

75

19

81

19

84

19

85

19

85

19

85

19

86

19

87

19

89

19

90

19

90

19

90

19

90

19

92

19

92

19

92

19

93

19

93

19

93

19

94

19

94

19

94

19

94

19

94

19

95

19

95

19

95

19

95

19

95

19

96

19

96

19

96

19

97

19

97

20

01

20

01

20

02

20

02

% Total Building Heat which is Gas

60%

80%

100%

% S

pace

Heat fr

om

Gas

Average of 69%, Majority of Space-Heat

Energy from Gas Sources

Hydronic Gas Heat

MURBs with fireplaces in

majority of suites

Space-Heat from Gas Sources

0%

20%

40%

60%

11

42

62

61

44 6

18

17

43 7

28

40

29

32 1 2

57

26 8

33

14

31 3

59

30

52

63

60 9

20

39

12

24

41

21

58

45

36

19

% S

pace

Heat fr

om

Gas

Current Misconceptions about High-Rise Energy Use

258 kWh/m2

128 kWh/m2

Actual ?>213 kWh/m2

HOUSES HIGHRISES

All of Canada

BC buildings use approximately 92% of the Canadian average

Appears that Common Area Gas Consumption (~50% of total energy use), may not have been included in SHEU data-set

Detailed Analysis

Heat Transfer

Model assemblies using THERM 5.2

Determining Thermals Resistance of Assemblies

Isothermal planes modeling technique

Three-Dimensional Components

Steel Stud

Interior Gypsum Wall Board Exterior Insulation

(Mineral Wool)

Cladding (Stucco)

Stud Sill Track

Stud Head Track

Concrete Floor Slab

Exterior Sheathing

Steel Z-girts

1) A cross-section is created

on the horizontal “blue” plane.

2) Components that vary

along the length of the wall are modeled using THERM

and equivalent

homogeneous materials are created.

3) A cross-section is created

on the vertical “green” plane.

4) The assembly is modeled

on this plane using THERM and the equivlanet

homogenous materials

created in Step 2 are used in place of inhomogeous

components as illustrated

at left.

Horizontal Cross-section Vertical Cross Section

Verify with HEAT 3D and previous Guarded Hot-Box testing results

Three-Dimensional Components

HEAT 3D model of 6” Stainless Steel Clip

Temperature Isotherms for 6” Stainless Steel Clip

Temperature Isotherms through stainless clip –horizontal cut

R-Values

Down Jacket

R 3-5

Acoustic Ceiling Tile

R 2

3.5’’ Fibreglass

Framed Wall with Batt Insulation

Steel stud wall assembly with concrete slab

R 12 or R14

R 3 - 4

3’’ XPS Insulation

Exterior Insulated Wall

Exterior insulated wall assembly

R 15

R 7.5

1’’ XPS Insulation

R5

Concrete Wall

Concrete wall with steel stud furring

R 7(R3 without XPS – Buildings 39 and 41)

3.5’’ Fibreglass

R14

U-Values

Window U-value

= Frame U x % Frame Area

+

Center of Glass U x % Glass Area

+

Edge of Glass U x % Edge of Glass Area

U-value = 1/R-value

Why do We Use U-Values for Windows?

Window Frame Material

Typical U-value

Typical R-value

% Heat Flow through Framing

Aluminum –

Small Thermal Break

0.550.550.550.55 1.821.821.821.82 60%60%60%60%

Aluminum – 0.390.390.390.39 2.582.582.582.58 45%45%45%45%

Because thermal performance is so poor?

Improved Thermal Break

0.390.390.390.39 2.582.582.582.58 45%45%45%45%

Insulated Vinyl or Fiberglass

0.270.270.270.27 3.73.73.73.7 23%23%23%23%

Spandrel Panels

Spandrels are poor thermal performers

Thermal bridging of insulation by frames

Effective R-value of spandrel panel assemblies are only slightly better than the windows themselves

Current project – original window sill detail

U-Values – What do we need?

Glazing = 0.24

U-Values – What do we need?

Glazing + Frame

= 0.37

Glazing + FrameGlazing + Frame+ Flashing

= 0.52

BC Energy Efficiency Act Requirement = 0.35

Building Design Requirement = 0.27

Shop Drawing Resubmission

U value = ?

Moisture Management ?

IGU Durability?

Model building in Google SketchUp

Determining Thermals Resistance of Assemblies

Wall Full Height at Window JambConcrete Wall at Outside Corner Wall Full Height at Window Jamb

Wall Under Window

Wall Full Height

Concrete Wall at Outside Corner

Concrete Wall at Inside Corner

Concrete Wall Full Height

Building 39 – Typical Newer High-rise

Enclosure Thermal Enclosure Thermal Enclosure Thermal Enclosure Thermal PerformancePerformancePerformancePerformance

Pre Rehabilitation RPre Rehabilitation RPre Rehabilitation RPre Rehabilitation R----valuevaluevaluevalue

hr fthr fthr fthr ft2222 F/BtuF/BtuF/BtuF/Btu

(m(m(m(m2222 K/W)K/W)K/W)K/W)

Effective Window R-value

1.58

(0.28)

Effective Wall Area R-value

2.95

(0.52)

Effective Roof R-value21.25(3.74)

Enclosure REnclosure REnclosure REnclosure R----valuevaluevaluevalue2.06(0.36)(0.36)(0.36)(0.36)

Enclosure R-value from energy consumption data 2.2

ASHRAE 90.1-2007 Compliance – Prescriptive Path

9

10

11

12

13

14

15

16

Overall Combined Wall and Window Enclosure R-value

Vinyl/Wood/Fiberglass - low-e/argon Triple IGUs, U-0.17

Vinyl/Wood/Fiberglass - low-e/argon Double IGUs, U-0.27

High Perf. Aluminum - low-

ASHRAE 90.1-2007 Compliance - Influence of Window Framing Type & IGU on Overall Enclosure R-value

Walls effective R-15.6, exterior insulated,clip

supports, minimal exposed slab edges

Arranged in order from

best to worst U-value

R2.06 < R3.75

0

1

2

3

4

5

6

7

8

9

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

% Window Area

Overall Combined Wall and Window Enclosure R-value

High Perf. Aluminum - low-e/argon Triple IGUs, U-0.29

High Perf. Aluminum - low-e/argon Double IGUs, U-0.39

High Perf. Aluminum - low-e/air Double IGUs, U-0.43

Typical Aluminum - low-e/airDouble IGUs, U-0.49

Minimum ASHRAE 90.1-2007Compliant, U-0.55

U-values from ASHRAE

tables & NFRC published

values

Compliant

Enclosure

Non-Compliant

Enclosure <R-3.75

Building 19 – Pre & Post Rehabilitation R-values

PrePrePrePre Rehabilitation Rehabilitation Rehabilitation Rehabilitation Post RehabilitationPost RehabilitationPost RehabilitationPost Rehabilitation Building #19 Pre and PBuilding #19 Pre and PBuilding #19 Pre and PBuilding #19 Pre and Poooost st st st RRRR----value value value value

IIIImmmmprovement provement provement provement Assembly DescriptionAssembly DescriptionAssembly DescriptionAssembly Description RRRR----vvvvaluealuealuealue Assembly Description Assembly Description Assembly Description Assembly Description RRRR----valuevaluevaluevalue

Walls (Walls (Walls (Walls (52% of enclosure)52% of enclosure)52% of enclosure)52% of enclosure)::::

Steel Stud w/ R-14 fiberglass.

Slab edges un-insulated,

balconies 3.93.93.93.9

Walls: Walls: Walls: Walls:

Exterior insulated, R-9.5 mineral

wool between steel z-girts. No

stud cavity insulation. Slab

edge insulated, balconies

uninsulated.

5.5.5.5.3333

WindowsWindowsWindowsWindows ( 27% of enclosure, ( 27% of enclosure, ( 27% of enclosure, ( 27% of enclosure, Windows:Windows:Windows:Windows:

34% of wall area)34% of wall area)34% of wall area)34% of wall area)::::

Non-thermally broken

aluminum frames. Clear glass,

air filled IGUs with aluminum

spacers

1.371.371.371.37

High performance thermally

broken aluminum frames. Soft-

coat low-e, air filled IGUs with

aluminum spacers

2.162.162.162.16

RoofRoofRoofRoof (21% of enclosure) (21% of enclosure) (21% of enclosure) (21% of enclosure)::::

Inverted assemblies with 3”

extruded polystyrene

14.14.14.14.3333

Roof:Roof:Roof:Roof:

Inverted assemblies with 4”

extruded polystyrene.

18.18.18.18.3333

OveralOveralOveralOverall Buildingl Buildingl Buildingl Building 2.922.922.922.92 Overall BuildingOverall BuildingOverall BuildingOverall Building 4.264.264.264.26

Rehabilitation improved RRehabilitation improved RRehabilitation improved RRehabilitation improved R----value by 46% (31% reduction in Uvalue by 46% (31% reduction in Uvalue by 46% (31% reduction in Uvalue by 46% (31% reduction in U----value)value)value)value)

Rehabilitation Resulted in a SpaceRehabilitation Resulted in a SpaceRehabilitation Resulted in a SpaceRehabilitation Resulted in a Space----Heat Savings of Approximately 10%Heat Savings of Approximately 10%Heat Savings of Approximately 10%Heat Savings of Approximately 10%

Pre- & Post-Rehabilitation R-values to assess space-heat savings

Calculated U-values for every detail of each wall, roof, window assembly

Calculated area-weighted U-values using detailed areas from sketch-up

Detailed R-value Calculations

PRE R-2.92 POST R-4.26

Typical Enclosure R-values – Study MURBs

2.92.92.92.9

3.33.33.33.3

3.53.53.53.5

3.13.13.13.1

3.63.63.63.6

3.33.33.33.3

3.63.63.63.6

4.34.34.34.34.14.14.14.1

3.03.03.03.0

3.53.53.53.5

4.04.04.04.0

4.54.54.54.5

Ove

rall E

ncl

osu

re R

-Valu

e - h

r ft

Ove

rall E

ncl

osu

re R

-Valu

e - h

r ft

Ove

rall E

ncl

osu

re R

-Valu

e - h

r ft

Ove

rall E

ncl

osu

re R

-Valu

e - h

r ft

22 22 F

/Btu

F/B

tu

F

/Btu

F/B

tu

Pre-Rehabilitation

Post-Rehabilitation

2.02.02.02.0 2.02.02.02.0 2.12.12.12.12.22.22.22.2 2.22.22.22.2

2.32.32.32.3

2.72.72.72.7 2.72.72.72.7

2.92.92.92.9

2.62.62.62.6

1.01.01.01.0

1.51.51.51.5

2.02.02.02.0

2.52.52.52.5

3.03.03.03.0

39393939 41414141 62626262 33333333 20202020 32323232 18181818 17171717 19191919 7777

Building ID

Ove

rall E

ncl

osu

re R

-Valu

e - h

r ft

Ove

rall E

ncl

osu

re R

-Valu

e - h

r ft

Ove

rall E

ncl

osu

re R

-Valu

e - h

r ft

Ove

rall E

ncl

osu

re R

-Valu

e - h

r ft

Typical Building R-value / Glazing Percentages

8

10

12

14

16

Overall Enclsosure R-value

R-16 ASHRAE 90.1

prescriptive minimum R-

value wall

R-10 Exterior

insulated wall with

no balconies &

minimal thermal

bridging Typical MURB Enclosure

0

2

4

6

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

% Window and Door Area

Overall Enclsosure R-value

R-2.5 High Performance

Aluminum Windows

R-1.3 Low Performance

Aluminum Windows

bridging

R-5 Typical

practice accounting

for thermal bridging

Typical MURB Enclosure

R-value R-2 to R-5

Overall

Whole Building Modeling

Facility Analysis and Simulation Tool (FAST)

Developed by EnerSys Analytics

Uses DOE-2 engine (same engine as eQuest, EE4)

Customized for Multi-Unit Residential Buildings

Whole Building Energy Simulation – FAST

Define building through series of inputs

Architectural

Mechanical

Space conditions


Program calculates monthly gas and electricity consumption


Model calibrations

Define set of starting estimates for unknown input parameters

Run simulation, compare simulation output to metered energy consumption (from bills)

Adjust unknown inputs so that simulation output matches metered consumption


metered consumption

Eg. Building 32: Suite Electricity

Decreased space heating (lowered baseboard capacity) to calibrate simulation to metered data


5%

10%

15%

20%

150,000

200,000

250,000DifferenceEnergy in kWh Avg. Monthly Error:

35.4% 9.7%

Ann. Error: 46.2%Uncalibrated

-20%

-15%

-10%

-5%

0%

0

50,000

100,000

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Billed

Simulated

Difference

-20%

-15%

-10%

-5%

0%

5%

10%

15%

20%

0

20,000

40,000

60,000

80,000

100,000

120,000

140,000


DifferenceEnergy in kWh

Billed

Simulated

Difference

Avg. Monthly Error: .0% 2.7%

Ann. Error: .1%Calibrated

Whole Building Modeling, Building 33

-20%

-15%

-10%

-5%

0%

5%

10%

15%

20%

0

50,000

100,000

150,000

200,000

250,000

300,000



Billed

Simulated

Difference

Avg. Monthly Error: 35.5% 8.3%

Ann. Error: 45.1%


-20%

-15%

-10%

-5%

0%

5%

10%

15%

20%

0

20,000

40,000

60,000

80,000

100,000

120,000

140,000

160,000



Billed

Simulated

Difference

Avg. Monthly Error: .1% 2.9%

Ann. Error: .1%

Un-calibrated results (45.1% annual difference)

Calibrated results (o.1 % annual difference)

Building 33 Modeling, Gas Consumption

-20%

-15%

-10%

-5%

0%

5%

10%

15%

20%

0

100

200

300

400

500

600

700

800


DifferenceNatural Gas in GJ

Billed

Simulated

Difference

Avg. Monthly Error: 24.9% .8%

Ann. Error: 24.1%


-20%

-15%

-10%

-5%

0%

5%

10%

15%

20%

0

100

200

300

400

500

600

700


DifferenceNatural Gas

Billed

Simulated

Difference

Avg. Monthly Error: -.6% 1.2%

Ann. Error: .8%

Un-calibrated results (24.1% annual difference)

Calibrated results (o.8 % annual difference)

Total building energy consumption = 164.4 kWh/m2/yr

Distribution of Energy Consumption – Building 33

Electric Baseboard Heating, 18.8, 9%

Fireplaces, 37.2, 19%Plug and

Appliances

Equipment and Ammenity

(Common), 28.3, 14%

Elevators, 4.2, 2%

19%

Ventilation Heating, 39.7,

20%DHW, 32.9, 17%

Lights - Common, 3.7, 2%

Lights - Suite, 15.9, 8%

Appliances (Suites), 18.7, 9%

Distribution of Energy Consumption - Modern MURB

Electric Baseboard

Heating, 29.1, 13%

Fireplaces, 24.1, 11%


Plug and Appliances

(Suites), 18.7, 9%


(Common), 19.9, 9%Elevators, 2.7, 1%


39%

DHW, 20.7, 9%



Modern MURB Modern MURB Modern MURB Modern MURB ---- >221.9 kWh/m>221.9 kWh/m>221.9 kWh/m>221.9 kWh/m2222

Heat

Building 11

Impact of Nominal R-Values In Modeling

53.5

38.040.0

50.0

60.0

An

nu

al S

pace

Heat C

onsum

pti

on, kW

h/m

An

nu

al S

pace

Heat C

onsum

pti

on, kW

h/m

An

nu

al S

pace

Heat C

onsum

pti

on, kW

h/m

An

nu

al S

pace

Heat C

onsum

pti

on, kW

h/m

22 22

0.0

10.0

20.0

30.0

Baseline Pre Nominal Assumptions

An

nu

al S

pace

Heat C

onsum

pti

on, kW

h/m

An

nu

al S

pace

Heat C

onsum

pti

on, kW

h/m

An

nu

al S

pace

Heat C

onsum

pti

on, kW

h/m

An

nu

al S

pace

Heat C

onsum

pti

on, kW

h/m

29 % Difference in Space Heat Energy Consumption

Calibrated models allow the assessment of other building systems

Other Building Systems

120

140

160

180

200

Nu

mb

er of S

uit

es

Nu

mb

er of S

uit

es

Nu

mb

er of S

uit

es

Nu

mb

er of S

uit

es

Buildings 7, 11, 32, 33

Building 18

0

20

40

60

80

100

120

0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00

Nu

mb

er of S

uit

es

Nu

mb

er of S

uit

es

Nu

mb

er of S

uit

es

Nu

mb

er of S

uit

es

Peak Average Daily Domestic Hot Water Consumption, gpmPeak Average Daily Domestic Hot Water Consumption, gpmPeak Average Daily Domestic Hot Water Consumption, gpmPeak Average Daily Domestic Hot Water Consumption, gpm

Domestic Hot Water

Other Building Systems

0.40

0.50

0.60

0.70

0.80

0.90

1.00

Po

wer

Densi

ty (W

/sf)

Po

wer

Densi

ty (W

/sf)

Po

wer

Densi

ty (W

/sf)

Po

wer

Densi

ty (W

/sf)

Suite Lighting

Suite Lighting and Plug Loads

0.00

0.10

0.20

0.30

0.40

0 10 20 30 40 50 60 70

Po

wer

Densi

ty (W

/sf)

Po

wer

Densi

ty (W

/sf)

Po

wer

Densi

ty (W

/sf)

Po

wer

Densi

ty (W

/sf)

Building NumberBuilding NumberBuilding NumberBuilding Number

Suite Plug Loads

Created a typical building model to run simulations

Typical Building Model

Typical Building Model Based on 13 Buildings

Average of 39 Study Buildings

Total Floor Area 121,922 ft² 118,655

Percent Area for Common Space 13%

Number of Suites 110 113

Number of Storeys (above grade) 18 18

Height of Average Storey 8.7 ft

Orientation from North 0 o

Gross Exposed Wall Area, Wall 1 15580 ft² Gross Exposed Wall Area, Wall 1 15580 ft²

Gross Exposed Wall Area, Wall 2 15580 ft²



Window Percentage, Wall 1 46% 47%




Infiltration Rate (0.15 cfm/sf) 0.572 ACH

Pre Post

Overall Roof R-Value 12.7 13.3 oF-ft²-hr/Btu

Overall Wall R-Value 3.6 5.5 oF-ft²-hr/Btu

Overall Window U-Value 0.70 0.51 Btu/oF-ft²-hr

Window Solar Heat Gain Coefficient 0.67 0.39

Architectural Inputs

Typical MURB uses approximately 200 kWh/m2/yr

Distribution of Energy Consumption

Electric Baseboard Heating, 18.8, 9%

Fireplaces, 37.2, 19%Plug and

Appliances


(Common), 28.3, 14%

Elevators, 4.2, 2%

19%


20%DHW, 32.9, 17%



Appliances (Suites), 18.7, 9%

Space Heat Consumption for locations across Canada

102.4

131.5

140.5144.8

120.9

129.1 129.4124.4

159.9

80

100

120

140

160

180

An

nu

al S

pace

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onsum

pti

on, kW

h/m

An

nu

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pace

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onsum

pti

on, kW

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An

nu

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pace

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on, kW

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22 22

0

20

40

60

80

Vancouver Calgary Edmonton Winnipeg Toronto Ottawa Montreal Halifax Whitehorse

An

nu

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An

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pace

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on, kW

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An

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pace

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on, kW

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on, kW

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Ottawa

Impact of Wall Performance on Space Heat Consumption

Window Influence on Total Building Energy

CoCoCoComparison of Different Window Performance Criteria on Total Building Energy Consumptionmparison of Different Window Performance Criteria on Total Building Energy Consumptionmparison of Different Window Performance Criteria on Total Building Energy Consumptionmparison of Different Window Performance Criteria on Total Building Energy Consumption

CaseCaseCaseCase Performance StandardPerformance StandardPerformance StandardPerformance Standard

(effective values)(effective values)(effective values)(effective values)

Overall Product Performance Overall Product Performance Overall Product Performance Overall Product Performance

CharacteristicsCharacteristicsCharacteristicsCharacteristics [W/(m[W/(m[W/(m[W/(m2222K]K]K]K]

Total Total Total Total

Heating Heating Heating Heating [kWh/m[kWh/m[kWh/m[kWh/m2222]]]]

Total Bldg Energy Total Bldg Energy Total Bldg Energy Total Bldg Energy

[kWh/m[kWh/m[kWh/m[kWh/m2222]]]]

% Total % Total % Total % Total

SavingsSavingsSavingsSavings

Baseline Average Pre Wall R-3.6

Roof R-12.7 Window U-3.97

U-3.97, SHGC-0.67 83.2 187.1 0.0%

Window U-3.97 SHGC-0.67

Window ASHRAE 90.1-2004 U-3.24, SHGC-0.4 83.3 187.2 -0.1%

ASHRAE 90.1-2007 U-3.1, SHGC-0.4 82.7 186.6 0.3%

ASHRAE 189.1-2009 U-2.57, SHGC-0.4 79.1 183.0 2.2%

BC EEA metal frame U-2.57, SHGC-0.4 79.1 183.0 2.2%

BC EEA non-metal frame U-2.0, SHGC-0.4 75.0 178.8 4.4%

Non-metal frame, low-e, argon fill, triple glazed

U-0.96, SHGC-0.3 67.6 171.5 8.4%

Lighting ASHRAE 90.1-2007 7.53 W/m2 83.7 185.5 0.9%

ASHRAE 189.1-2009 6.78 W/m2 84.1 184.4 1.4%

Impact of Window Performance on Space Heat

60

80

100

120

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22 22

Electricity

0

20

40

60

Baseline U = 0.45SHGC = 0.4

U = 0.45SHGC = 0.3

U = 0.27SHGC = 0.4

U = 0.27SHGC = 0.3

U = 0.17SHGC = 0.3

U = 0.17SHGC = 0.2

Post U-Value with Pre SHGC

An

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Electricity

Gas

Air Flow

Space Heat Loss Distribution – Effect of Air Leakage

Mechanical

Natural Air

Leakage, 2.9,

3%

Natural Air

Leakage,

16.3, 16%

Conduction,

Air Tight Enclosure Air Leaky Enclosure – Open Windows

Conduction,

47.9, 53%

Mechanical

Ventilation,

39.7, 44%

Mechanical

Ventilation,

39.7, 38%

Conduction,

47.9, 46%

kWh/m2/yr, % Total Space Heat kWh/m2/yr, % Total Space Heat

Total Space Heat = 90.5 kWh/m2/yr


Natural Air

Leakage, 2.5,

22%Conduction,

2.3, 20%

What if Good Enclosure & w/Heat Recovery Ventilation?

Air Tight Enclosure Air Leaky Enclosure – Open Windows

Mechanical

Ventilation

24%

Conduction

5%

Mechanical

Ventilation,

6.5, 58%

kWh/m2/yr, % Total Space Heat kWh/m2/yr, % Total Space Heat


Natural Air

Leakage

71%


Assumed flow rate of 50 cfm per suite

Impact of Different Make-up Air Flow Rates

125.0

100

120

140

160

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22 22

25.1 25.1 25.2 25.3 25.3 25.4 25.4 25.5 25.6 26.7 24.0

77.4 75.7 74.0 71.5 69.8 68.2 66.5 64.1 62.644.2

125.0

0

20

40

60

80

100% of Nominal*

95% of Nominal

90% of Nominal

85% of Nominal

80% of Nominal

75% of Nominal

70% of Nominal

65% of Nominal

60% of Nominal

Zero Modern

An

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on, kW

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Gas

Understanding Energy Use in MURBs

Electric BaseboardHeaters in all

Gas fireplaces insome Suites

Air exhausted usingbathroom/kitchen fans

& windows

Air leakage of heatedventilation air through

elevator and stairwell shafts Ventilation air is heatedusing gas-fired make-up

air unit (MUA)

HeatedVentilation airfrom corridor

Domestic HotWater is heated

using Gas

- To heat ventilation air for make-up air supply- To heat domestic hot water- To heat pool/hot-tubs- Suite fireplaces (if equipped)- Pilot lights for above

- Interior lighting

Air flow throughopen windows

Elevator pumping

Parking GarageExhaust Fans

Parking Garage

Common Areas

PoolGas Boiler toheat pool &

hot-tubs

Suites

Heaters in allSuites

Some Gas & ElectricHeat at Common Areas

Typically Unheated

Rec. Areas

- Interior lighting- Elevators- Ventilation fans and motors- Parking garage exhaust fans- Water distribution pumps- Baseboard heaters- Recreation areas/pool pumps- Exterior lighting- Communication- Controls

- Baseboard heaters- Lighting- Appliances- Miscellaneous Electric Loads- Plug loads- Exhaust fans

Enclosure air-leakage

Air Flow within a Building

Building 20

Air Pressure Differential in Study Building (43)

22 storey highrise - Pressure Beneath Suite Doors

14

15

16

17

18

19

20

21

22

Theoretical

Average

Maximum

Linear (Theoretical)

Linear (Average) Measured air pressure across the corridor doors

-15 -10 -5 0 5 10 15

2

3

4

5

6

7

8

9

10

11

12

14

Flo

or

Pressure Differential (Pa)

Linear (Maximum) across the corridor doors of suites in a 22 storey building

Make-Up air Considerations

1. We should be ventilating for health and comfort (not heat)

2. Corridors need a minimal amount of air for smoke/odour control but fresh air is needed in the suites.

3. Reconsider large rooftop MUA units & pressurized corridor supply for ventilation.

4. Provide fresh air-directly to suites4. Provide fresh air-directly to suites

5. Compartmentalization is needed

• Further research of air flow within buildings required

Investigation and analysis of condensation related problems at window-wall assemblies.

Monitored environmental conditions and mechanical system conditions:

Make-Up Air Investigation

Temperatures

Relative HumidityRelative Humidity

CO2

Operation of mechanical

equipment including

Heat pump

Cloths dryer

Exhaust Fans

Make-up air at suite door

Make-Up Air Investigation

Actual Airflow

2959Kitchen Fan - Level 3



1455Common Bathroom Fan

1153Guest Bathroom Fan

855Master Bathroom Fan

0 cfm24 cfmBaseline (no fans operational)

N301N601

Suite Number

27%183%% of ASHRAE Recommended with Continuous Master Bath Fan

0%79%% of ASHRAE Recommended @ Baseline

30 cfm30 cfmASHRAE Recommended (based on # of occupants, 15cfm/person)

10%67%% of ASHRAE Recommended with Continuous Master Bath Fan

0%29%% of ASHRAE Recommended @ Baseline

82 cfm82 cfmASHRAE Recommended (based on suite size = 0.3 ACH)

1455Dryer w/ Booster Fan


ASHRAE recommendations at 15 cfm per person for actual occupant loads

ASHRAE recommendations based on suite area (accounts for 5-6 occupants)

Air flow less affected by fan operation, hallway pressurization was not working

Control suite

Other Considerations

Fireplaces

Occupants

etc.

Other Considerations

77.4

80

100

120A

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22 22

Impact of Fireplaces – Why do we need them?

25.1 29.1

77.4

39.9

0

20

40

60

Baseline Pre With Fireplaces

Baseline Pre Without Fireplaces

An

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An

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pace

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on, kW

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pace

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on, kW

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Gas

Electricity

Distribution of Energy Costs in MURBs

Total

Consumed By

Owner, 59.5,

29%Total

Consumed By

Strata, 146.9 ,

Electric

Baseboard

Heating, 24.8,

42%

Lights (Suite),

15.9, 27%

Plug and

Appliances

(Suite), 18.7,

31%

Owner PaidStrata, 146.9 ,

71%

Electric Baseboard

Heating, 0.3 , 0%

Fireplaces, 37.7 ,

26%

Ventilation Heating,

39.7 , 27%

DHW, 32.9 , 22%

Lights (Common),

3.7 , 3%

Equipment and

Ammenity

(Common), 28.3 ,

19%

Elevators, 4.2 , 3%

Owner Paid

Strata Paid

Average MURB Energy Distribution and Associated Cost

28% Suite Electricity = $408/yr (Occupant Paid)

21% Common Area Electricity = $323/yr (Strata Paid)

51% Gas Heat and Hot water = $455/yr (Strata Paid)

Only 36% of Total Energy Cost is Directly Paid by Occupant

Disconnect Between Consumption and Billing

Only 36% of Total Energy Cost is Directly Paid by Occupant

69% of Building Space Heat is from Gas (Paid by Strata)

Occupants are only directly paying for 31% of space heating

How Do We Do Better?

New Buildings to be Carbon Neutral by 2020

Where Do We Want To Go?

Biggest Opportunities in Existing Buildings

Reduce the loads

Getting to “Best Performance” Space Heating

Recover the heat

Impact of Cladding Attachment – R-15 of Insulation

Current Practice

R-7.4

Better

R-10.3

Even Better

R-11.6 to 14.4

Most Efficient

R-15.8

Retrofit and New Construction Enclosure Strategies

6

7

8

9

10

Ove

rall C

om

bin

ed

Wall a

nd

Win

dow

Encl

osu

re R

-valu

e

ASHRAE 90.1-2007 Compliance - Influence of Window Framing Type on Overall Enclosure R-value

Thermally Efficient Building Enclosures

Constructed with high performance

windows and well insulated walls

0

1

2

3

4

5

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

% Window Area

Ove

rall C

om

bin

ed

Wall a

nd

Win

dow

Encl

osu

re R

-valu

e

Study Buildings - Metro Vancouver

Average 50% glazing area

ASHRAE 90.1 - 2007 Compliant Buildings

Constructed with minimally compliant

wall and window R-values

Thermal Anatomy of a High Rise MURB

R-12 Insulation in wallsR-4 accounting for steel studs and slab edges

R-1.8 Windows aluminum window wall, low-e, air fillR-20 Roof Insulation65% Glazing

R-Value % of Enclosure % Heat loss

Walls 4 29 16.6

Strategy 1 Improve wall R-value to R10Strategy 2 Improve window R-value to R3.5Strategy 3 Reduce window area to 30%

Walls 4 29 16.6

Windows 1.8 65 82.7

Roof 20 6 0.7

Overall R-Value

2.3

Strategy 1 Improve wall R-value to R10


Walls 10 29 7.4

Windows 1.8 65 91.9

Roof 20 6 0.8

Overall R-Value

2.52.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

Base Strategy 1

Strategy 2 Improve Window R-value to R3.5


Walls 10 29 13.3

Windows 3.5 65 85.3

Roof 20 6 1.4

Overall R-Value

4.65.0

0.0

1.0

2.0

3.0

4.0

5.0

Base Strategy 1 Strategy 2

Strategy 3 Reduce Glazing to 30%

R-Value % of Enclosure % Heat lossWalls 10 64 41.9Windows 3.5 30 56.1Roof 20 6 2.0

Overall R-Value

6.57.0

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

Base Strategy 1 Strategy 2 Strategy 3

Reduced Glazing Area

Improved Ventilation Strategies

Corridor pressurized with small fans at each floor level

Combination Energy Efficiency Measures Simulated

ScenarioScenarioScenarioScenario Model InputsModel InputsModel InputsModel Inputs

Baseline Post

t Walls effective R-5.5 t Windows double glazed, air fill, low-e, aluminum frame; U = 0.51, SC = 0.45 t Air tightness “Tight – High Average”, 0.15 cfm/ft2 t Make-up air temperature setpoint 68°F t No heat recovery

Good t Walls effective R-10 t Windows double glazed, argon fill, low-e, low conductive frame; U = 0.27, SC

= 0.35 = 0.35 t Air tightness “Tight – Low Average”, 0.05 cfm/ft2 t Make-up air temperature setpoint 64°F t No heat recovery

Best t Walls effective R-18.2 t Windows triple glazed, argon fill, low-e, low conductive frame; U = 0.17, SC =

0.23 t Air tightness “Very Tight”, 0.02 cfm/ft2 t Make-up air temperature setpoint 60°F t 80% Heat Recovery

Simulated Space Heat Consumption Scenarios

102.4

95.6

67.4

80.0

100.0

120.0

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onsum

pti

on, kW

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on, kW

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22 22

Better windows, walls and air-tightness

Ventilation Heat-Recovery

45.0

38.2

9.7

0.0

20.0

40.0

60.0

Baseline Pre Baseline Post Good Best Good, WithoutFireplaces

Best, WithoutFireplaces

An

nu

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pace

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pti

on, kW

h/m

An

nu

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pace

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onsum

pti

on, kW

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An

nu

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pace

Heat C

onsum

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on, kW

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An

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onsum

pti

on, kW

h/m

Total Building Energy Use

Can get ~100 kWh/m2/yr with ventilation and enclosure upgrades only

Further improvements from Domestic Hot Water, Lighting, Appliances, Controls etc.

200

250

An

nu

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y Co

nsu

mp

tio

n, kW

h/m

An

nu

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y Co

nsu

mp

tio

n, kW

h/m

An

nu

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y Co

nsu

mp

tio

n, kW

h/m

An

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y Co

nsu

mp

tio

n, kW

h/m

22 22

110.3 109.897.5

76.960.8

39.4

96.0 89.7

73.8

72.181.3

74.2

0

50

100

150

Baseline Pre Baseline Post Good Best Good, WithoutFireplaces

Best, WithoutFireplaces

An

nu

al Energ

y Co

nsu

mp

tio

n, kW

h/m

An

nu

al Energ

y Co

nsu

mp

tio

n, kW

h/m

An

nu

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y Co

nsu

mp

tio

n, kW

h/m

An

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y Co

nsu

mp

tio

n, kW

h/m

Gas

Electricity

R-Values

How Do We Get To Net Zero?

20

25

30

35

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nua

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e E

lectr

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pace

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onsu

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on

, kW

h/m

An

nua

l Suit

e E

lectr

ic S

pace

Heat C

onsu

mpti

on

, kW

h/m

An

nua

l Suit

e E

lectr

ic S

pace

Heat C

onsu

mpti

on

, kW

h/m

An

nua

l Suit

e E

lectr

ic S

pace

Heat C

onsu

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on

, kW

h/m

22 22

U = 0.45, 50% WWR

U = 0.45, 40% WWR

U = 0.45, 30% WWR

U = 0.45, 20% WWR

0

5

10

15

0 5 10 15 20 25 30 35 40 45 50

An

nua

l Suit

e E

lectr

ic S

pace

Heat C

onsu

mpti

on

, kW

h/m

An

nua

l Suit

e E

lectr

ic S

pace

Heat C

onsu

mpti

on

, kW

h/m

An

nua

l Suit

e E

lectr

ic S

pace

Heat C

onsu

mpti

on

, kW

h/m

An

nua

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e E

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pace

Heat C

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on

, kW

h/m

Wall Effective RWall Effective RWall Effective RWall Effective R----Value (hrValue (hrValue (hrValue (hr----ftftftft2222----F/Btu)F/Btu)F/Btu)F/Btu)

U = 0.45, 20% WWR

U = 0.27, 50% WWR

U = 0.27, 40% WWR

U = 0.27, 30% WWR

U = 0.27, 20% WWR

U = 0.17, 50% WWR

U = 0.17, 40% WWR

U = 0.17, 30% WWR

U = 0.17, 20% WWR

Near Net Zero – Effective Control of Air Flow

20

25

30

35

40

An

nu

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uite E

lect

ric

Sp

ace

Heat C

onsum

pti

on, kW

h/m

An

nu

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uite E

lect

ric

Sp

ace

Heat C

onsum

pti

on, kW

h/m

An

nu

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uite E

lect

ric

Sp

ace

Heat C

onsum

pti

on, kW

h/m

An

nu

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uite E

lect

ric

Sp

ace

Heat C

onsum

pti

on, kW

h/m

22 22

Enclosure 1: Windows U-0.17, 30% WWR,

Walls R-18.2

0

5

10

15

20

0 0.2 0.4 0.6 0.8 1

An

nu

al S

uite E

lect

ric

Sp

ace

Heat C

onsum

pti

on, kW

h/m

An

nu

al S

uite E

lect

ric

Sp

ace

Heat C

onsum

pti

on, kW

h/m

An

nu

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uite E

lect

ric

Sp

ace

Heat C

onsum

pti

on, kW

h/m

An

nu

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uite E

lect

ric

Sp

ace

Heat C

onsum

pti

on, kW

h/m

Air Leakage Rate, cfm/sfAir Leakage Rate, cfm/sfAir Leakage Rate, cfm/sfAir Leakage Rate, cfm/sf

Walls R-18.2

Enclosure 2: Windows U-0.45, 40% WWR,

Walls R-15.6

Typical Building

Simulated Air Leakage

Rate

Increased risk of moisture problems in more energy efficient buildings

Consider future maintenance and renewal costs

Final Thoughts - Energy Efficiency & Moisture Problems

Failure of “thermo-cladding”

Systemic LowSystemic LowSystemic LowSystemic Low----e e e e corrosion within corrosion within corrosion within corrosion within proprietary triple IGUs proprietary triple IGUs proprietary triple IGUs proprietary triple IGUs after 5 years after 5 years after 5 years after 5 years

Need for a New Approach

Courtesy of Bunting Coady Architects

Integrated Design Process

A New Approach for the Design of Buildings

Discussion

Further Information / Background Information

CMHC Reports / Guides

Homeowner Protection Office Bulletins and Guides

Builder Insight No. 7

Building Enclosure Design Guide

Low-rise Requirements

BC Energy Efficiency Act - Windows

ProductProductProductProduct Maximum UMaximum UMaximum UMaximum U----ValueValueValueValueW/(m2·K) BTU/(hr·ft2·K)

Effective DateEffective DateEffective DateEffective Date

Vinyl and fibreglass windows and sliding doors

2.0 0.35 March 1, 2009

Tested with CSA A440.2-04 or NFRC 100-2004

Third party testing (SCC or NFRC accredited labs)

Permanent certification label, temporary U-value label

Exempts heritage buildings

Wood windows and sliding glass doors 2.0 0.35 January 1, 2011

Metal windows and sliding glass doors 2.57 0.452.0 0.35

June 1, 2009January 1, 2011

Skylights (for low-rise and high-rise) 3.1 0.54 March 1, 2009

High-rise Requirements

BC Energy Efficiency Act - Windows

ProductProductProductProduct Maximum UMaximum UMaximum UMaximum U----ValueValueValueValueW/(m2·K) BTU/(hr·ft2·K)

Effective DateEffective DateEffective DateEffective Date

Metal framed curtain wall, window wall and storefront products

2.57 0.45 January 1, 2011

Exempts products installed in buildings that are compliant with ASHRAE 90.1 (04 or 07)

Option for U-value “certificate” in lieu of labels

Flexibility provided for structural windows

and storefront products

Windows with framing materials other than metal, with or without metal reinforcing or cladding

2.0 0.35 January 1, 2011

Improved Ventilation Strategies

Corridor pressurized with small fans at each floor level

Questions?

energy consumption in mid-and high-rise residential buildings

Documents