CLIMA 2007 ConferenceJune 2007

William Fisk Olli Seppanen

Providing Better Indoor Environmental Quality Brings Economic Benefits*

Lawrence Berkeley National Laboratory

Helsinki University of Technology

*with significant contributions from Pawel Wargocki and colleagues at the Danish Technical University

How Better IEQ Can Improve Health & Productivity

Superior Work Performance Economic

Benefits

Better Health Reduced Health Care Costs

Less Absence

•Thermal state• Hearing and concentration

•Vision• Mood

•Mental performance

Improved Indoor Environmental

Quality

Better design, construction,

commissioning & O&M

The Costs of People Overshadow Building Costs

050

100

Rel

ativ

e C

ost

Energy

Maintenance

Rent

Salaries &Benefits

Significance

Very small percentageimprovements in work performance will pay for large percentage increases in operation and maintenance costs.

Source : Woods (1989) Occupational Medicine 4: 753-770

Health Care Costs Are Substantial

0

500

1000

1500

2000

2500

3000

3500

4000

4500

$ B

illio

ns

EmployeeCompensation

Total HealthExpenditure

Private Sector HealthInsurance

Commercial BuildingEnergy

*U.S. Data from 1995 or 1996

How the Impact of IEQ on Health and Performance Has Been Studied

Experimental modifications of temperature, ventilation rates, pollutant sources, etc. in laboratory, office building, call center, or classroom

Speed, accuracy of simulated work or simulated school workSpeed of interaction with call center clients plus information processingChange in prevalence of a health outcome

Cross sectional surveys of large numbers of offices or classrooms with natural building-to building variability in ventilation rate, temperature, or another IEQ parameter

Surveys of health symptomsRecording of absence daysPerformance on academic achievement testsClinical documentation of cases of disease

Benefits of Better Control

of Indoor Temperature

% Change in performance per 1 oC increase in temperature: Results of 24 studies

-10

010

20

Del

ta P

%/C

15 20 25 30 35

Temperature (C)

rep orted in each study

composite weighted

90 % CI of composite weighted

sample size wei gh ted

un weighted

Unweighted

Sample-size weighted

Sample size & outcome weighted

% In

crea

se in

Per

form

ance

per

1 o C

Mostly > 0

Mostly < 0

Relative Work Performance vs. Temperature(maximum performance at at 21.8 oC, 72 oF )

.8.8

5.9

.95

1

Rel

ativ

e P

erfo

rman

ce

15 20 25 30 35

Temperature (°C)

Performance Reduction Is Statistically

Significant Where Shaded Green

Estimated Economic Value of Work Performance Changes from 1 oC (1.8 oF) Shift

in Temperature Toward Optimum

Temp. Change Increase in Performance

Annual Economic Benefit Per Worker*

19 to 20 oC66.2 to 68 oF

0.9%680 €

$90020 to 21 oC

68 to 69.8 oF0.4%

300 €$400

23 to 22 oC73.4 to 71.6 oF

0.3%230 € $300

24 to 23 oC75.2 to 73.4 oF

0.6%460 € $600

*Assuming 760000 € ($100K) cost per worker for salaries and benefits

Temperature and School Work

70

80

90

100

110

120

18 20 22 24 26Temperature

Nor

mal

ized

per

form

ance

(spe

ed)

oC

%

R2=0.46; P<0.001

School Work Speed is Affected by Temperature

Source: Wargocki and Wyon, ASHRAE Journal, October 2006

Temperature and School WorkSchool Work Accuracy is Not Significantly Affected by Temperature

70

80

90

100

110

120

18 20 22 24 26Temperature

Nor

mal

ized

per

form

ance

(err

ors)

oC

%

R2<0.01; P<0.99

Source: Wargocki and Wyon, ASHRAE Journal, October 2006

Avoiding High Temperatures can also reduce Sick Building Syndrome (SBS) Symptoms

Relative risk for SBS-symptoms per degree C increase in temperature

00.20.40.60.8

11.21.41.6

20 21 22 23 24 25

Average temperature oC

RR

for S

BS

per o C

No effect

20% increase in symptoms

Example Benefit-Cost Analyses of Cooling a Helsinki Office Building

Factor Base Case

Mechanical

Cooling

Increased Operation

Time (No Mech. Cooling)

Increased Outdoor Air

Flow (No Mech. Cooling)

Increased annual energy plus first cost per person, €

-- 54 6.3 95

Effective lost work hours per person-year, h 21.2 15.5 12.6 6.5

Value of lost work hours per person-year, € 686 501 408 211

Value of improved work, € -- 184 278 475

Total annual savings per person, €

-- 131 272 380

Source: Wargocki et. al (2006) REHVA Guidebook 6 [65000 € per employee-year]

Importance of Building

Ventilation*

*outdoor air supply

% Increase in work performance per 10 L/s-person increase in ventilation rate

-4-2

02

46

Del

ta P

%/(1

0 L/

s-pe

rson

)

0 10 20 30 40 50

Ventilation Rate (L/s-person)

reported in each studycomposite weighted

95% CI of composite weighted

90% CI of composite weighted

sample size weighted

unweighted

Unweighted

Sample-size weighted

Sample size & outcome weighted

Perf

orm

ance

Cha

nge

( %)

Ventilation Rate L/s-person

90% CI

95% CI

1 L/s = 2 cfm

Performance relative to performance with 6.5 L/s-person (13 cfm/person)

1

1.01

1.02

1.03

1.04

1.05

0 10 20 30 40 50

Ventilation Rate (L/s per person)

Rel

ativ

e W

ork

Perf

orm

ance

Current code min. for most U.S. offices

Current code min. for most U.S. schools

Result of Analyses of 8 Studies with 24 Total Data Points

RP = (5.56 x 10-8) V.3–(1.48 x 10-5) V 2 + (1.49 x 10-3) T + 0.983

Source: Seppanen, Fisk, Lei-Gomez (Indoor Air Journal 2005)

Ventilation Rates and Performance in SchoolsResults of a Danish Study* - Work Speed

*Wargocki and Wyon, ASHRAE Journal, October 2006

School Work Speed Increases with Ventilation Rate

70

80

90

100

110

120

0 2 4 6 8 10

Outdoor air supply rate

Nor

mal

ized

per

form

ance

(spe

ed)

L/s/person

%

R2=0.43; P<0.001

Ventilation Rates and Performance in SchoolsResults of a Danish Study* - Work Errors

*Wargocki and Wyon, ASHRAE Journal, October 2006

School Work Errors Not Significantly Affected by Ventilation Rate

70

80

90

100

110

120

0 2 4 6 8 10

Outdoor air supply rate

Nor

mal

ized

per

form

ance

(erro

rs)

L/s/person

%

R2=0.02; P<0.30

Decrease in Respiratory Illness or Absence With Increased Ventilation Rates

Source: Fisk Annual Rev. E&E 2000

0

10

20

30

40

50

60

70

1

% D

ecre

ase

HigherVent. Rate

inBarracks

1000 ppmless CO2

inClassrooms

HigherVent. Rate

More spacein Nursing

Home

Higher Vent. Rate

in Jail

Higher Vent.

Rate inOffices

Respiratory Illness

AbsenceAll reductions statistically significant

An example of data on ventilation and short term sick leave of office workers

Milton et al. (2000) Indoor Air Journal

Short term sick leave

0.0

0.5

1.0

1.5

2.0

12 L/s 24 L/s per person

1.45 %

2.00 %

1.5 daysper year

460 € ($600) per worker per year

with annual cost of 76000 € ($100000)40 buildings

in study

24 cfm 48 cfm per person

Sick Building Syndrome (SBS) Symptoms Increase With Decreased Ventilation rate

With lower ventilation rate:

20 of 27 studies found statistically significant increase in symptoms9 studies found >80% increase in prevalence of at least one symptom

Suggestion of benefits of increasing ventilation rate up to about 20 L/s-person

Source: Seppanen et al. Indoor Air 1999

Wor

kday

avg

. ∆C

O2

Odds Ratio

∆CO2 Reference100% increase in symptomsResults of a

Critical Review

Estimated Average Value of 5 L/s-person (10 cfm/person) Increase in Minimum

Ventilation RateBetter Work Performance

0.42% performance increase+ 320 € ($420) per worker per year*

Reduced Absence0.7 days per year +190 € ($250) per worker per year

*at 76000 € ($100K) annual salary plus benefits

Analyses of Energy and Non-Energy Benefits of Economizer Systems

Economizer BackgroundPurpose

Reduce HVAC energyMaintain minimum vent. rate

MethodUse outdoor air for cooling when less expensive than mechanical cooling

UsageCommon in large HVACConsidered too expensive for small HVAC

Outdoor Temp. 25 oC

100% Code Minimum

% O

utdo

or A

ir

No economizer

Estimated Annual Benefits of Economizer in a Washington D.C. Office Building

Estimated savings from increased work performance and reduced illness-related

absence is 50 times the energy cost savings,

Increase in annual average vent. rate 10 L/s-person Normally considered benefit Annual Energy cost savings

23 € ($30) per person

Normally neglected benefits Annual value of reduced absence* Annual value of productivity increase Total

320 € ($420) per person 760 € ($1000) per person 1080 € ($1420) per person

*estimated with disease transmission model calibrated with empirical data; 76000 € ($100K) annual compensation

Benefits of Indoor Pollutant Source Control

In Some Cases Removal of Pollutant Sources* has Increased Work Performance

*Unlike increased ventilation, pollutant source control usually consumes no energy

90

92

94

96

98

100 P<0.0001

sourcepresent

sourceabsent

sourceabsent

sourcepresent

3 10 30

Per

form

ance

(%)

L/s per person

Source was sample of carpet from a complaint building

Source: Pawel Wargocki, Danish Technical University

Possible Health-Related Economic Benefits of Eliminating Indoor Tobacco

Smoking in the U.S.

0.0E+00

4.0E+08

8.0E+08

1.2E+09

1.6E+09

Ann

ual C

ost p

er 1

06 Pop

ulat

ion

(€)

Mobidity Premature Death

Low

er B

ound

Low

er B

ound

Upp

er B

ound

Upp

er B

ound

Asthma

Bronchitis & PneumoniaBased on

estimated numbers and unit costs for health effectsPotential savings are higher in much of Europe because of higher smoking rates

Cost of Damp and Moldy Homes

Increase Risks in Damp or Moldy Homes

Cough 50%Wheeze 44%Asthma Development 30%Current Asthma 50%

Percentage of US Homes with Dampness or Mold

47%

Asthma Attributable to Home Dampness or Mold

4.6 million cases in U.S.

21%

Annual Health Cost of Asthma in U.S.

$16.8 Billion

Cost of Asthma Attributable to Home Dampness and Mold

21%

$3.5 Billion/ year in U.S.

Statistical Analyses of 33 Studies

Average of 6 Studies

Update of Two Prior Analyses

Workplace Dampness or Mold Also Increases Risks of Health Effects

Few studies, but nearly all find increased health effectsExamples

US office building with history of dampness: Current asthma was 120% > normal; adult onset of asthma was 230% > normal; 12% of sick leave attributable to respiratory symptoms at workWorking in moldy buildings in Finland 54% more adults developed asthmaIn 80 complaint US office buildings where drainage of cooling coil drain pan was poor, number of occupants with multiple asthma symptoms was increased by 260%*

*Note: Findings not replicated in analyses of data from 100 non-complaint office buildings

SummaryBetter temperature control Large potential financial benefits from improved work performance Increased ventilation rates up to ~ 20 L/s per person Large potential financial benefits from improved work performance and healthReducing indoor pollutant sources Substantial potential economic benefits from improved work performance and health

Without the energy needed for increased ventilationIndoor tobacco smoking and dampness deserve special attention

Potential economic benefits are large relative to costs of improved building design or operation

Benefit cost ratios can exceed 10Per employee savings up to 500 € per year

LimitationsUncertainty in magnitude of work performance and health improvements remains large

Improvements will vary among buildings and with type of work and with outdoor air qualityBenefits may be distributed among employer, building owner, employee

Research to date has not evaluated how IEQ affects high level cognitive performance such as critical decision makingCost benefit analyses have not accounted for true long term cost of energy use and climate change

Strongly encourage use of energy efficient technologies and practices to improve IEQ

We don’t yet understand why or how IEQ affects work performance

Motivation? Metabolic rate? Fatigue? Mental processing?

What You Can DoMake greater effort to design buildings that improve IEQ while saving energyImplement periodic or continuous commissioning to maintain building and HVAC performanceEducate building professionalsDevelop incentives for better IEQDevelop better methods to integrate energy conservation and IEQ improvement

Current PracticeAims for:

Adequate IEQ

Future PracticeAims for:IEQ that

MaximizesHealth &

Performance

Future PracticeAims for Large Energy Savings