SATISFACTION AND SELF-ESTIMATED PERFORMANCE IN RELATION TO INDOOR ENVIRONMENTAL PARAMETERS AND BUILDING FEATURES Pawel Wargocki1, Monika Frontczak1,2, Stefano Schiavon2, John Goins2, Ed Arens2 and Hui Zhang2 1International Centre for Indoor Environment and Energy, DTU Civil Engineering, Technical University of Denmark 2Center for Built Environment, University of California, Berkeley, USA Presentation given at the Workplace Trends 2012 Conference: Wellbeing and Performance, Thursday 25 October 2012, One Bishop's Square, London, E1 6AD.

1. SATISFACTION AND SELF-ESTIMATED
PERFORMANCE IN RELATION TO INDOOR
ENVIRONMENTAL PARAMETERS AND
BUILDING FEATURES
Pawel Wargocki1 (Monika Frontczak1,2, Stefano Schiavon2,
John Goins2, Ed Arens2 and Hui Zhang2)
1InternationalCentre for Indoor Environment and Energy, DTU Civil
Engineering, Technical University of Denmark
2Center for Built Environment, University of California, Berkeley, USA

2. Research regarding thermal and air quality
effects on performance
24-10-2012

3. Ventilation and performance of office work
(in relation to 6.5 L/s per person)
1.05
1.04
Performance
1.03
1.02
1.01
1.00
0 10 20 30 40 50 60
Outdoor air supply rate (L/s per person)
24-10-2012
Source: Wargocki and Seppanen (2006)

4. Temperature and performance of office
work
1.00
0.95
Performance
0.90
0.85
0.80
0.75
15 20 25 30 35
Temperature (°C)
24-10-2012
Source: Seppanen et al. (2005)

5. BACKGROUND
 Occupants of buildings are exposed to all indoor
environmental parameters simultaneously
 It is likely that comfort is a result of a combined effect of
different IEQ parameters
 It is also likely the quality of building including furniture,
colors and other building amenities contribute to
satisfaction with indoor environment
 Standards for IEQ provide requirements for single
parameters not their combination
 Very few studies on the combined effects of IEQ
parameters and building features on human comfort
and satisfaction
 Some studies have shown that satisfaction with IEQ is
related with the self-estimated job performance
24-10-2012

6. HANEDA ET AL. 2008
24-10-2012

7. OBJECTIVES
 To investigate which subjectively evaluated
indoor environmental quality parameters and
building features mostly affect satisfaction and
self-estimated job performance in office
buildings
 To examine the link between occupants’
satisfaction with their personal workspace and
self-estimated job performance
 To quantify the size of the effects
24-10-2012

8. DATA
 Data collected by the survey conducted by Center for the Built
Environment (CBE)
 Data collected over a 10-year period in 600 buildings (offices,
hospitals, schools,…)
 Present study: 52,980 responses from occupants in 351 office
buildings, mainly located in the U.S. (397 surveys)
 Background questions (gender, age, type of work performed,
office type, distance from a window)
 Questions re. perceived satisfaction and self-estimated
performance
 Building information form filled out by building facility manager
providing information about the building and its systems:
building’s age, location and size, number of floors, number of
occupants, type of HVAC system, solar shading and controls,
buildings’ LEED rating, energy use and cost of building 24-10-2012
construction, etc.

9. PERCEIVED SATISFACTION
 Amount of space  Air quality
 Visual privacy  Amount of light
 Ease of interaction  Visual comfort
 Furniture comfort  Noise level
 Furniture adjustability  Sound privacy
 Color & texture of surroundings  Building cleanliness
 Temperature  Workspace cleanliness
 Building maintenance
24-10-2012

10. OBSERVED SATISFACTION LEVELS
24-10-2012

11. SELF-ESTIMATED JOB PERFORMANCE
……………………………
 Air quality
 Office layout  Thermal comfort
 Office furnishings  Lighting quality
 Acoustic quality
 Cleanliness and maintenance
of the building
24-10-2012

12. OBSERVED SELF-ESTIMATED JOB PERFORMANCE
24-10-2012

13. IMPACT OF INDOOR ENVIRONMENTAL QUALITY AND BUILDING
FEATURES ON SELF-ESTIMATED JOB PERFORMANCE
 24%: no effect
 33%: job
performance
decreased by
environmental
conditions by at least
5%
24-10-2012

14. STATISTICAL ANALYSIS
 Workspace satisfaction = f(satisfaction with environmental
and building parameters) using proportional odds logistic
regression (odds ratios: the strength of association between
variables)
 Self-estimated job performance = f(satisfaction with
personal workspace) using simple linear regression
(regression coefficient: percentage change of self-estimated
job performance caused by a unit change of a predictor
variable)
 Self-estimated job performance = f(satisfaction with
environmental and building parameters) using multivariate
linear regression (regression coefficient: percentage change
of self-estimated job performance caused by a unit change
of a predictor variable) 24-10-2012

15. WORKSPACE SATISFACTION AS A FUNCTION OF INDOOR
ENVIRONMENTAL PARAMETERS AND BUILDING FEATURES
 All parameters statistically
significant (p<0.05)
 The most important
parameters: satisfaction
with amount of space,
noise level and visual
privacy
 Satisfaction with amount of
space the most important
regardless occupants’
gender and age, type of
office (single office, shared
office, cubicles) and
distance from a window
24-10-2012

16. AMOUNT OF SPACE VS. AREA PER PERSON
 Satisfaction with amount of
space almost independent
of area per person
 Spearman rank correlation
ρ=0.03, p<0.001
 Limitations
 A rough estimation of real
area per person
 No data on amount of
storage space in a vertical
direction
24-10-2012

17. SATISFACTION VS. OFFICE TYPE
 Occupants in private
offices more satisfied
with workspace than
those in shared offices or
cubicles (p<0.001)
24-10-2012

18. SATISFACTION VS. WINDOW DISTANCE
 Occupants close to a
window more satisfied
with workspace than
those further from a
window (p<0.001)
24-10-2012

19. SELF-ESTIMATED JOB PERFORMANCE AS A FUNCTION OF
SATISFACTION WITH INDOOR ENVIRONMENTAL PARAMETERS AND
BUILDING FEATURES
 The most important
parameters: satisfaction
with temperature, noise
level and air quality
 One-unit (~15%) increase
in satisfaction with
temperature would
increase self-estimated
job performance by
about 1%
24-10-2012

20. SELF-ESTIMATED JOB PERFORMANCE AS A
FUNCTION OF SATISFACTION WITH WORKSPACE
 Workspace satisfaction affects self-estimated
job performance
 Statistically
significant (p<0.001)
 Regression coefficient with 95% CI: 3.72 (3.67-
3.78)
 One-unit (~15%) increase in satisfaction with
workspace would increase self-estimated job
performance by about 3.72%
24-10-2012

21. %
100 Simulated office work (lab)
98
Performance
96
94
(R2=0.784; P=0.008)
92
110
90 Office work (call centre)
Performance
0 10 20 30 40 50 60 70 % 105
Dissatisfied with air quality
100
95
90
0 10 20 30
Outdoor air supply rate
(L/s per person)
Elevated temperatures and poor air quality can affect
performance of adults by 5% (laboratory) to 10% (field), and
schoolwork of children by over 20% (field)
24-10-2012
Source: Wargocki et al. (1998; 2004)

22. CONCLUSIONS
 Lowest satisfaction levels observed for sound privacy
and temperature
 Building occupants generally satisfied with their
personal workspace
 In order to increase overall satisfaction with personal
workspace, increase firstly satisfaction with amount of
space, noise level and visual privacy
 Self-estimated job performance affected by workspace
satisfaction
 The biggest increase in self-estimated job performance
achieved by increasing satisfaction with temperature,
noise level and air quality
24-10-2012

23. DISCUSSION OF DISCREPANCY BETWEEN RANKING OF
PARAMETERS RE. THEIR IMPORTANCE FOR SATISFACTION
AND PERFORMANCE
 No clear explanation
 Amount of space is likely related to the status
and position at work, the higher status the
higher satisfaction
 Status may not be related to performance
 Changes to indoor environmental parameters
easier “correlated” (memorized) by individuals
with work performance than building features
24-10-2012

24. IMPLICATIONS
 Present results can guide building users,
operators and employers in making decisions
on how working indoor environment can be
improved most effectively by selecting these
parameters which promote comfort and
working morale at the most
24-10-2012

25. Productivity gain of just
10% would offset the full
running and installation
costs
Although there is some
level of uncertainty to
which extent IEQ affects
productivity even
improvements <1% are
COST-EFFECTIVE
THE EFFECTS ARE SUFFICIENTLY HIGH TO PROMOTE
INVESTMENTS IN HIGH INDOOR ENVIRONMENTAL QUALITY
Source: Wargocki and Seppänen (2006); Building Value, Energy Design Guidelines
24-10-2012
for State BuildingsOffice of the State Architect, California (1976

26. The primary
purpose of
office building
is to provide
an optimal
conditions for
work
and not to
conserve
energy
24-10-2012

27. BUILDING CERTIFICATION SCHEMES, LEED
 Provide a framework to design and build green buildings as well as
to assess sustainable building performance.
 Is voluntary, though considered prestigious.
 Have been on the construction market for the last 15 years and are
not anymore a niche segment.
LEED Section Possible Points
Sustainable sites 26 Points
Water efficiency 10 Points
Energy and atmosphere 35 Points
Materials and resources 14 Points
Indoor environmental Quality 15 Points
Total 100 Points
Innovation in Design 6 Points
Regional priority 4 Points
24-10-2012

28. BUILDING CERTIFICATION SCHEMES, BREEAM
BREEAM adopts a ‘balanced score-card’ approach to the assessment and rating of building
performance; to achieve a particular level of performance the majority of BREEAM credits can be
traded.
BREEAM sets minimum standards of performance in key areas like energy, water, waste etc.
24-10-2012

29. THANK YOU, QUESTIONS?
24-10-2012

30. Thank you
paw@byg.dtu.dk
24-10-2012