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4
Benefits and Costs Associated with High-Performance or Green Buildings:
Summary of the Literature Review
The Committee on Energy-Efficiency and Sustainability Standards Used by the Department of
Defense for Military Construction and Repair was tasked to conduct a literature review that synthesizes
the state-of-the-knowledge about the costs and benefits, return on investment, and long-term payback of
specified American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) design
standards and green building certification systems. The committee identified numerous publications,
ranging from studies with clearly outlined design objectives and methodologies and empirical
information, to individual case studies and opinion editorials. In Chapters 1 and 3, the committee
identified factors that made its task more complex. Additional factors became apparent as the committee
reviewed the literature, as outlined below.
• Baselines and definitions. As noted in Chapter 3, baselines for measuring the energy and
water use and operations and maintenance costs for buildings are limited, and it is difficult to quantify the
benefits and costs of those factors. The equally important but more difficult to quantify effects, such as
worker health, productivity, and well being, are typically treated qualitatively, although quantitative
measures are sometimes developed for these factors. Typically information about indoor environmental
quality (IEQ),1 which relates to health, well being, and productivity, are gathered through surveys of
building occupants, which introduces a level of subjectivity that is not present when resources are
monitored through engineered systems.
There are no national baselines for measuring occupant satisfaction with indoor environmental
quality or for measuring worker productivity related to building design. Standard survey forms to collect
data from building users have been developed by the Center for the Built Environment (CBE) at the
University of California, Berkeley, and the Usable Buildings Trust in the United Kingdom.2 Data
gathered from the CBE surveys have been collected in a single database from which baselines can be
developed for comparative studies. As of October 2009, the CBE database included 51,000 individual
responses from occupants of 475 buildings (CBE, 2012). As of 2011, the Usable Buildings database
contained surveys of occupants of 500 buildings in 17 countries (Baird et al., 2012).
Studies on high-performance or green buildings use a wide range of definitions to describe the
criteria/attributes of the buildings being evaluated. In some studies, green buildings are defined as
Leadership in Energy and Environmental Design (LEED)-certified. In others, the green building sample
may include a mix of LEED-certified buildings, LEED-registered buildings, buildings receiving industry
awards, and buildings designed with energy efficiency as an objective. This variance in definitions, like
the variance in baselines, makes it difficult to objectively compare the results of one study to another.
• Types of buildings and sizes. Each of the studies reviewed included a variety of building
types in the sample sets for green buildings, ranging from office buildings to schools, hospitals, and
laboratories to courthouses. Different building types and different building sizes incorporate different
types of mechanical and other systems to meet differing needs in terms of hours of operation (24/7 or
1
Indoor environmental quality typically refers to factors such as temperature, humidity, ventilation, lighting,
and noise.
2
See http://www.usablebuildings.co.uk.
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weekdays only), use, intensity of use, number of floors, and other factors. Generalizing findings across a
mix of building types and sizes introduces another set of confounding factors that prevent an apples-to-
apples comparison across studies.
Given those factors, the factors identified in Chapters 1 and 3, and a 6-month time frame to
complete its work, the committee determined it would need to focus solely on the main purposes of the
statement of task. For its evaluation of the research literature, the committee determined that it would rely
on studies that met the following criteria:
• Timeframe. The committee relied on studies published in 2004 or later because the first
studies evaluating the incremental costs of LEED-certified buildings were published in 2004. The first
evaluations of a sample of at least six high-performance or green buildings were published in 2006.
• Robustness. The committee focused on studies with clearly stated objectives, a clearly
defined methodology, findings based on empirical data, and a sample size of at least six buildings. The
committee relied more heavily on those studies that reported measured results for energy (utility bills)
than on modeled or predicted results, because the committee believes that data from actual buildings will
be more reflective of the type of results that DOD can expect from its high-performance buildings.
Because the number of green buildings is increasing each year, more recent studies can
incorporate larger sample sizes from which to make comparisons. Larger sample sizes can help to
eliminate some factors of bias, error, and chance that are prevalent in individual case studies, although
such factors may still be present.
• Relevance to the DOD operating environment. The research literature on high-performance
and green buildings includes a number of reports that analyze the market and price effects of LEED or
ENERGY STAR®3-certified buildings (primarily office buildings) compared to conventional buildings in
terms rental rates, vacancy rates, turnover ratios, appraised value, and other factors (Miller et al., 2008;
Chappell and Corps, 2009; Dermisi, 2009; Fuerst, 2009; Fuerst and McAllister, 2008; Fuerst et al., 2010;
Conlan and Glavis, 2012; Eicholz et al., 2009, 2011). These studies are of value, particularly to the
private sector and to federal agencies such as the General Services Administration (GSA), which secures
commercial space for other agencies. However, because DOD primarily owns and operates its facilities
for 30 years or longer, the committee did not analyze these studies in detail, because market-related
factors such as rental premiums and appraised value are not directly relevant to the DOD operating
environment. The committee instead relied on studies that focused on energy and water use, indoor
environmental quality, and other factors that DOD is required to address through the Energy
Independence and Security Act of 2007 and other mandates.
OVERVIEW OF FINDINGS FROM THE STUDIES ANALYZED
The committee did not identify any studies that conducted a traditional benefit-cost analysis to
determine the long-term net present value savings, return on investment, or long-term payback related to
the use of ASHRAE standards 90.1-2010 and 189.1-2011 and the LEED or Green Globes green building
certification systems. Only two studies (Turner, 2006; Kats, 2010) compared the performance of green
buildings (defined differently) to conventional buildings (different baselines) and assigned some measure
of net present value (NPV) to different categories of costs and benefits.
The committee also did not identify any studies that analyzed the performance of samples of six
or more Green Globes-certified buildings; the only evaluations of the performance of Green Globes-
certified buildings were individual case studies.
3
ENERGY STAR® is a labeling program for energy-efficient building-related products and equipment. It is not
a green building certification system.
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The data cited for the 25 studies that met the committee’s criteria are not universally unique; that
is, some studies evaluated all or portions of the same data sets. For example, one of the most robust
studies of green buildings conducted to date is Energy Performance of LEED for New Construction
Buildings (Turner and Frankel, 2008). Turner and Frankel gave other researchers access to their data set
for green buildings. Thus, studies published by Newsham et al. (2009) and by Scofield (2009a, 2009b)
used the same data set but applied different analytical tests and arrived at different conclusions. In a
different instance, Fowler and Rauch (2008) analyzed 12 green buildings owned and operated by the
GSA. Fowler et al. (2010) reanalyzed the original 12 buildings, updated the available data, and also
included 10 additional GSA green buildings in their analysis.
For the ease of the reader, the findings from the 25 studies are organized by specific topic area—
energy use, water use, operations and maintenance costs, indoor environmental quality and productivity,
and incremental costs to design and construct high-performance buildings. Where studies are cited more
than once, the first reference includes some basic information about the sample size, definitions,
methodology, and other factors. This information is not repeated if the study is cited multiple times. Table
4.1 contains summary information about the studies cited. They are arranged in the order that they first
appear in Chapter 4. More detailed information about each of the studies is contained in Appendix D.
TABLE 4.1 Studies Evaluated and Some of Their Characteristics
Characteristics of High-
Authors and Study Performance or Green Building
Title Sample Variables Measured Methodology
Torcellini et al. Six high-performance Net source energy used; Monitored six buildings
(2006) buildings defined as designed net site energy used intensively over a 4-year
Lessons Learned to achieve aggressive energy (both measured as period; gathered at least 1
from Case Studies of goals; buildings constructed energy use intensity year of energy use and costs
Six High- between 1996 and 2005; six (EUI); energy costs for each building; compared
Performance building types; a range of actual costs to baseline energy
Buildings locations models for the buildings and
to energy-code compliant
base-line buildings
Diamond et al. 21 LEED-NC buildings Baseline energy Compared the actual site
(2006) certified between 2001 and modeled; design energy energy use of 18 of the 21
Evaluating the 2005; 14 federal and 7 non- modeled; actual energy buildings, based on utility
Energy Performance federal; 8 office, 4 laboratories, use, all expressed as bills, to the baseline energy
of the First 1 library, 3 multifamily, 4 EUI; ENERGY STAR® and design energy models
Generation of mixed use, 1 education scores (illustrative); submitted for the LEED
LEED-Certified LEED energy- certification process; also
Commercial efficiency-related points compared simulated whole
Buildings building energy to actual
billed energy
Turner and Frankel 121 LEED-NC-certified Site energy (EUI) actual, Compared the actual site
(2008) buildings; 100 buildings modeled for total sample energy use of 121 LEED-
Energy Performance classified as “medium energy and subsets of sample, certified buildings to CBECS
of LEED® for New use activities” (office and including office (35 national averages, ENERGY
Construction similar); 21 buildings as “high buildings) and LEED STAR® ratings, and LEED
Buildings energy use activities” (data certification levels baseline energy models;
centers, laboratories, and (Certified, Silver, evaluated energy use of
similar) Gold/Platinum; also medium-energy-use buildings,
collected data on high-energy-use buildings, 35
occupant satisfaction office buildings, and for
buildings at different LEED
certification levels
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Characteristics of High-
Authors and Study Performance or Green Building
Title Sample Variables Measured Methodology
Newsham et al. 100 LEED-certified buildings Site energy (EUI) actual, Reanalyzed a data set from
(2009) categorized as “medium energy modeled; site energy use Turner and Frankel (2008),
Do LEED-certified use activities”; same data for buildings certified as applying t-tests and other
buildings save subset as Turner and Frankel LEED Certified, Silver, statistical measures to provide
energy? Yes, but … (2008) Gold/Platinum more rigor; individually
matched LEED-buildings in
data set to similar non-LEED-
certified buildings in the
CBECS database
Scofield (2009a) 100 LEED-certified buildings Site energy use; source Defined mean EUI differently
A Re-Examination of categorized as “medium energy energy use; energy use than two other studies;
the NBI LEED use activities”; same data by LEED certification measured source energy as
Building Energy subset as Turner and Frankel level well as site energy and
Consumption Study (2008) and Newsham et al. conducted statistical tests
(2009)
Scofield (2009b) 35 LEED-certified office Site energy; source Weighted EUI of each
Do LEED-Certified buildings; same subset of data energy building by its gross square
Buildings Save used by Turner and Frankel feet; used different averaging
Energy? Not Really (2008) methods than other studies
Kats (2010) 170 green buildings of a wide Incremental costs of Conducted benefit-cost
Greening Our Built range of types, located in 33 green design and analysis and payback analyses
World: Costs, states and 8 countries; green construction; energy use for energy use and water use
Benefits, and buildings defined as LEED- and costs; water use and of green versus conventional
Strategies certified, anticipating LEED costs; data reported for buildings; data for green
certification or certified under all buildings in sample buildings primarily based on
another similar system (none and by LEED- models, not actual measured
certified under Green Globes) certification level data
Fowler and Rauch 12 General Services Site energy use, water Measured energy use based
(2008) Administration (GSA) use, operating costs, on utility bills and compared
Assessing Green buildings designed to be occupant satisfaction to CBECs national and
Building LEED-certified or otherwise regional averages and GSA
Performance: A Post designated green; 6 office, 4 baselines; measured water use
Occupancy courthouses, 2 combination based on utility bills and
Evaluation of 12 office/courthouse compared to a derived
GSA Buildings baseline for domestic water
use; compared operating costs
to industry sources;
distributed CBE survey to
measure occupant satisfaction
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Characteristics of High-
Authors and Study Performance or Green Building
Title Sample Variables Measured Methodology
Fowler et al. (2010) Updated data for 12 GSA Same measures as Same methodology as Fowler
Re-Assessing Green green buildings studies by Fowler and Rauch and Rauch (2008); also
Building Fowler and Rauch (2008); (2008) provided analyses of a subset
Performance: A Post expanded data set to include 10 of 15 LEED-certified
Occupancy additional GSA green buildings by certification
Evaluation of 22 buildings; total sample level (Certified, Silver,
GSA Buildings included 8 courthouses, 12 Gold/Platinum)
office buildings, and 2 mixed
office/courthouse
Menassa et al. (2012) 11 Naval Facilities Site energy use for 11 Compared measured site and
Energy Consumption Engineering Command buildings; water use for water use for the LEED-
Evaluation of U.S. (NAVFAC) buildings LEED- 9 buildings (2 LEED- certified buildings to
Navy LEED- certified by 2008, included 3 Certified, 4 LEED- measured energy and water
Certified Buildings LEED-certified, 5 LEED- Silver, 3 LEED-Gold) use for 11 similar NAVFAC
Silver, 3 LEED-Gold buildings that were not LEED
buildings; 1 drill hall, 3 certified
maintenance facilities, 1
laboratory, 1 child care center,
2 barracks, 1 golf course
clubhouse, 2 administration
buildings
Turner (2006) 11 LEED-certified buildings in Site energy use; indoor Compared actual energy use
LEED Building the Pacific Northwest; sample water use; NPV benefits (utility bills) and water use to
Performance in the included 7 offices or libraries for energy and water; three baselines: initial model
Cascadia Region: A and 4 multi-family buildings; 3 occupant satisfaction projections, baseline
Post Occupancy LEED-NC-certified, 4 LEED- approximate to code, and
Evaluation Report NC-Silver, 3 LEED-NC-Gold, ENERGY STAR® median;
1 LEED-EB-Gold NPV calculations assumed a
25-year time period, discount
rate of 3 percent, and utility
rate increases equal to rate of
inflation
Baylon and Storm 24 LEED-certified buildings Site energy use (EUI) Compared the characteristics
(2008) constructed between 2002 and of the LEED-certified
Comparison of 2005 in the Pacific Northwest. buildings to a larger sample of
Commercial LEED 8 different building types; most contemporary buildings built
Buildings and Non- buildings had been occupied at to local standard codes;
LEED Buildings least 2 years characteristics studied
within the 2002-2004 included lighting, HVAC
Pacific Northwest systems, building envelope,
Commercial Building glazing, and control systems
Stock
Sacari et al. (2007) 19 new or renovated green Site energy use Compared actual site energy
Green Buildings in buildings in Massachusetts, use in the green buildings to
Massachusetts: including 12 green schools and the energy use predicted by
Comparison Between 6 other buildings that were design models and to energy
Actual and Predicted LEED-certified use in buildings constructed
Energy Performance to Massachusetts code
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Characteristics of High-
Authors and Study Performance or Green Building
Title Sample Variables Measured Methodology
Widener (2009) 25 LEED-certified projects in Energy use (EUI); green Compared data for the LEED-
Regional Green Illinois including projects house gas emissions; certified projects to three
Building Case Study certified under a variety of water use (indoor and other data sets/baselines:
Project: A Post- LEED programs; at least 6 outdoor); commute Turner and Frankel (2008),
Occupancy Study of different building types; most transportation; CBECs national averages, and
LEED Projects in certified under LEED versions construction and ENERGY STAR®; single data
Illinois 2.0 or 2.1 operating costs; green element that was mandatory
premium, health and for inclusion in the sample
other benefits; occupant was post-occupancy measured
comfort energy use
Oates and Sullivan 25 LEED-NC-certified Site energy (EUI); Actual energy performance of
(2012) buildings in Arizona; 7 source energy (EUI) the LEED-certified buildings
Postoccupancy building types certified under was compared to national
Energy Consumption LEED versions 2.0, 2.1, and averages from the CBECs
Survey of Arizona’s 2.2; all had been in operation at database; CBECS data
LEED New least 1 year as of October normalized to match the gross
Construction 2009; sample broken into 19 square feet weights for each
Population buildings with medium energy building type in the LEED
intensity (offices and similar) sample
and 6 buildings of high energy
intensity (laboratories)
Leonardo Academy 11 to 13 buildings certified LEED-EB certification Gathered data from building
(2008) under LEED-EB program as of costs; operating costs owners on costs to certify
The Economics of 2007 buildings under the LEED-EB
LEED for Existing program (13 buildings);
Buildings for collected data on operating
Individual Buildings costs for 11 buildings and
compared them to industry
sources
Abbaszadeh et al. 21 green office buildings of Overall occupant Surveyed occupants of green
(2006) which 15 were LEED-certified satisfaction; thermal buildings directly using
Occupant and 6 had received green or comfort, air quality, questionnaire developed by
Satisfaction with energy efficiency awards lighting, and CBE; compared results to
Indoor acoustics/noise remaining buildings in CBE
Environmental database (conventional)
Quality in Green
Buildings
Miller et al. (2009) 154 buildings that were LEED- Productivity measured Conducted a survey of more
Green Buildings and certified or had an ENERGY as sick days and self than 2,000 tenants in 154
Productivity STAR® label; located across reported productivity buildings; also calculated the
the country percentage after moving economic impacts of those
into a green building tenants who claimed an
increase in productivity
(report summarized a
literature review as well)
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Characteristics of High-
Authors and Study Performance or Green Building
Title Sample Variables Measured Methodology
Baird et al. (2012) 31 sustainably designed Occupant satisfaction Distributed a questionnaire
A Comparison of the commercial or institutional overall; occupant developed for the Buildings In
Performance of buildings located in 11 satisfaction with Use (BIU) studies to 2,035
Sustainable countries; occupied by 15 to temperature, lighting, tenants in 31 green buildings;
Buildings with 350 staff; 15 office, 10 and acoustics/noise compared results to data for
Conventional education, 4 laboratories, 2 occupants in 109
Buildings from the mixed use conventionally designed
Point of View of the buildings from the BIU
Users database that had been
surveyed during a similar time
period
Matthiessen and 45 LEED-seeking buildings Incremental construction Compared the construction
Morris (2004) from the database of the Davis costs of green buildings costs of 45 LEED-seeking
Costing Green: A Langdon Company buildings to the construction
Comprehensive Cost costs of 93 non-LEED-
Database and seeking buildings; all costs
Budgeting were normalized for time and
Methodology location to ensure consistency
for the comparisons
Matthiessen and 83 buildings seeking LEED Incremental construction Compared the construction
Morris (2007) certification under versions 2.1 costs of green buildings costs of 83 LEED-seeking
and 2.2; building types buildings to the construction
included academic classrooms, costs of 138 non-LEED-
laboratories, libraries, seeking buildings; all costs
community centers, and were normalized for time and
ambulatory care facilities location to ensure consistency
for the comparisons
Steven Winter Study undertaken to estimate Incremental construction Individual LEED credit
Associates (2004) the costs to develop green costs for federal assessments and cost
GSA LEED Cost federal buildings using LEED courthouses and office estimates were completed for
Study 2.1; examined a 5-story buildings six different scenarios to
courthouse and a mid-rise create a cost range for LEED
federal office building Certified, Silver, and Gold,
levels
Indian Health Study undertaken to evaluate Incremental construction Evaluated initial capital cost
Service (IHS) (2006) potential cost impacts of costs for hospitals and investments and life-cycle
LEED Cost achieving LEED-NC and other healthcare-related costs (20-year period); LEED
Evaluation Study LEED-NC-Silver certification buildings credits were evaluated against
on IHS facilities standard practices of the IHS
as outlined in the IHS design
guide
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Characteristics of High-
Authors and Study Performance or Green Building
Title Sample Variables Measured Methodology
Caprio and Soulek Five standard building types Incremental construction Study undertaken to identify
(2011) most commonly constructed by costs; total energy use incremental construction costs
MILCON Energy the U.S. Army: barracks, (modeled) for building energy efficiency
Efficiency and tactical equipment and enhancements intended to
Sustainability Study maintenance facility, meet federal mandates
of Five Types of government office and other
Army Building public assembly, brigade
headquarters, and dining
facility
ENERGY USE
Sixteen studies focused solely or in part on the site energy use in high-performance or green
buildings. They are organized below into three categories: studies of energy use in commercial buildings;
studies of energy use in federal buildings; and regional studies of energy use.
The majority of the studies measured energy use intensity (EUI), typically calculated by taking
the total energy consumed in 1 year (measured in kBtu) and divided by total building floor area to
compare the performance of green to conventional buildings. Most studies measured site energy, although
a few measured source energy. Measurement of source energy brings into play issues and policies related
to the reduction of greenhouse gas emissions, which is beyond the scope of the committee’s statement of
task. For that reason, the committee primarily reports study results in terms of site energy.
Studies of Energy Use in Commercial Buildings
Torcellini et al. (2006) conducted field evaluations over a 4-year period for six high-performance
buildings of different types and in different geographic areas. High-performance buildings were defined
as those that were designed to meet energy-savings goals ranging from 40 percent better than energy-code
compliant buildings to net-zero-energy buildings. All used innovative technologies and a whole building
design process to look at the interrelationships of each building’s technologies, materials, and design. The
researchers compared source and site energy performance (at least 1 year of measured performance) and
the energy costs of each of the buildings to energy-code-compliant base-case buildings. They found that
the six high-performance buildings used between 25 percent and 79 percent less site energy than the
baseline buildings. Site energy costs were 12 to 67 percent lower than the energy costs for the baseline
buildings. The variability in energy cost savings was attributed to differences in utility rate structures, fuel
types, and peak demand profiles, among other factors.
Diamond et al. (2006) measured the actual energy use of 21 LEED-certified buildings (utility
bills for the first year of operation) against the energy use predicted by the energy-use baseline and design
models submitted for the same buildings for LEED certification. For the 18 buildings in the sample for
which the researchers had both simulated whole building energy use and actual purchased energy data,
the actual energy use was 28 percent lower than for the baseline model. However, there was significant
variation among individual buildings, with some being more energy efficient than predicted and some
being less efficient. For a subset of nine federal buildings, the actual energy use was lower than the
modeled use.
Turner and Frankel (2008) reviewed the post-occupancy energy performance of 121 LEED-NC-
certified buildings, of which 100 were classified as “medium energy use activities” and defined as
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buildings that had energy use intensities (EUIs) in a range similar to office buildings. (Total EUI was
derived by summing the purchased energy for all fuel types.) Twenty-one buildings were classified as
“high-energy use activities,” which included buildings with very high process loads, such as laboratories,
data centers, and recreation facilities. Most of the analyses in the report focused on the 100 medium-
energy-use buildings. Within the 100-building sample, at least eight building types were included, and
office was the predominant use. Thirty-eight of those buildings were certified as LEED-NC-certified; 35
as LEED-NC-Silver; and 27 as LEED-NC-Gold or -Platinum.
The report compared measured energy use (1 full year of post-occupancy energy use) to several
different benchmarks, including CBECS national averages, ENERGY STAR® ratings, and modeled
energy performance predictions provided as part of the submittals for LEED certification. They found that
for all 121 LEED-certified buildings, the median measured site EUI was 24 percent lower than the
CBECS national average (as of 2003) for all commercial building stock. For 35 office buildings in the
LEED-certified sample, the average energy use was 33 percent lower than the CBECS national average
for office buildings. The authors found that project types classified as high-energy-use activities with high
process loads, such as laboratories, were problematic, because the energy use of high-energy-use building
types is not well understood by designers.
Within the sample of 100 medium-energy-use activities, Turner and Frankel found that LEED-
NC-Certified buildings used 26 percent less site energy than the CBECS national average, LEED-NC-
Silver buildings used 32 percent less energy, and LEED-NC-Gold/Platinum-certified buildings used 44
percent less energy on average than the CBECS national average. The authors also compared the actual
energy use in the LEED-certified buildings to the energy use predicted by baseline and design models
submitted for the buildings as part of the LEED certification process. In this instance, measured energy
use for the buildings was 28 percent less on average than the energy baseline models (most used
ASHRAE Standard 90.1-1999) and 25 percent less on average than the levels predicted by the design
models. However, the energy use for more than half of the projects deviated by more than 25 percent
from design projections, with 30 percent significantly better and 25 percent significantly worse.
For all but the warm-to-hot zones, LEED-NC buildings used significantly less energy than the
CBECS national average, with median LEED EUIs 36 to 49 percent lower than the CBECS average for
those zones. For the warm-to-hot zones, the median LEED EUI was virtually the same as CBECS. The
authors stated that “the current variability between predicted and measured performance has significant
implications for the accuracy of prospective life-cycle cost valuations for any given building” (Turner and
Frankel, 2008, p. 5).
Newsham et al. (2009) re-analyzed the data used in Turner and Frankel (2008) for the 100 LEED-
NC buildings categorized as “medium energy use activities.” They employed a range of statistical tests to
improve the rigor of the analysis. In the tests, Newsham et al. sought to pair each LEED building with a
single matched building from the CBECS database. Newsham et al. noted that a limitation of the Turner
and Frankel study was that the comparisons to the CBECS data were somewhat crude:
The median EUI of all LEED buildings was compared to the mean EUI of all CBECS buildings,
by activity type, thus confounding two different metrics of central tendency. Little specific
account was made of differences in the two datasets related to climate zone, building size, or
building age (Newsham et al., 2009, p. 5).
Nonetheless, Newsham et al. found that:
• No matter the basis of comparison, the LEED-certified buildings used statistically significant
less energy per floor area than the CBECS averages. On average, the LEED-certified buildings used 18 to
39 percent less energy per floor area.
• Twenty-eight to 35 percent of LEED-certified buildings used more energy per floor area than
their individually matched buildings from the CBECS database.
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• There was no statistically significant relationship between LEED-NC certification level and
energy use intensity or percent energy saved versus the baseline. LEED-NC-Silver buildings did not
exhibit better energy performance than LEED-NC-certified buildings and LEED-NC-Gold/Platinum
buildings did not exhibit better energy performance than LEED-NC Silver buildings. This finding was the
opposite of the finding from the Turner and Frankel (2008) study.
Scofield published two separate papers that reanalyzed subsets of the Turner and Frankel data
(Scofield, 2009a, b). In both cases, Scofield included source energy, whereas Turner and Frankel (2008)
and Newsham et al. (2009) used site energy only.
In the report A Re-examination of the NBI LEED Building Energy Consumption Study (Scofield,
2009a), Scofield pointed out Turner and Frankel’s comparison of the mean of one distribution to the
median of another and stated that “to compare the mean of one with the median of the other introduces
bias by compensating for skew in only one distribution” (Scofield, 2009a, p. 765). Scofield also defined
mean energy intensity differently, using a gross square foot averaging method, and conducted statistical
tests of the data for several subsets of the Turner and Frankel database. Scofield compared data from
some of the LEED-certified buildings to the CBECS database and also to a subset of buildings from
CBECS constructed between 2000 and 2003. His conclusions included the following:
• LEED-certified medium-energy-use buildings, on average, used 10 percent less site energy
than did other comparable commercial buildings, whether restricted to new vintage (constructed between
2000 and 2003) or not.
• LEED-NC-certified buildings used slightly more site energy than the CBECS comparison
group, while LEED-Silver and LEED-Gold or -Platinum buildings used 23 percent and 31 percent less
site energy, respectively, than the CBECS comparison group.
• LEED office buildings used 17 percent less energy than that of the CBECS comparison group
of all vintages.
In the paper “Do LEED-certified buildings save energy? Not really. . .” (Scofield, 2009b),
Scofield reanalyzed data from Turner and Frankel (2008) for a subset of 35 LEED-certified office
buildings. Scofield weighted the energy intensity of each building in the LEED sample by its gross square
footage, which he stated was exactly equal to the total energy use by all buildings divided by their total
gross square feet. In doing so, Scofield pointed out that different averaging methods would yield different
means and different conclusions. Nonetheless, Scofield found that:
• LEED-NC-certified office buildings used, on average, 10 to 17 percent less site energy than
comparable non-LEED buildings.
• Smaller LEED office buildings had relatively lower purchased EUI (relative to non-LEED),
while larger LEED office buildings showed less savings in comparison to non-LEED buildings.
Kats (2010) analyzed data for 170 green buildings representing of a wide range of building types
located in 33 states and 8 countries. The primary emphasis of this study was on the financial benefits and
costs of green buildings in comparison to conventional buildings. Data related to the incremental costs of
green construction, energy use and water use, and other measures were gathered directly from building
owners, architects, and developers. The results of the survey were synthesized with the findings from
other studies to develop estimates of the NPV of benefits and costs. Other studies used in the synthesis
included surveys, case studies, and market research.
The buildings in the sample were completed between 1998 and 2009. Green buildings were
defined as those that were LEED-certified or anticipating LEED certification or certification under
another similar rating system. Approximately 15 percent of the 170 buildings were certified under
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systems such as the Massachusetts green schools guidelines, Enterprise Green Communities, or the Green
Guide for Healthcare Facilities.
Reported reductions in energy use for the green buildings were measured as EUI and largely
based on computer design and baseline models submitted as part of the LEED certification process, not
on actual measured energy use (utility bills) for the buildings. Kats (2010) reported that the buildings in
the data set had projected reductions in energy use, from less than 10 percent to more than 100 percent
(meaning that the building generated more power than it used), with a median reduction of 34 percent.
However, Kats also noted that even within a single building type and region, green and conventional
buildings showed a wide range of energy intensities depending on factors such as building design,
mechanical systems and appliances, operations and maintenance practices, and occupancy.
For the benefit-cost analyses to calculate NPV benefits, Kats used a time period of 20 years, a
discount rate of 7 percent, and assumed annual inflation rates of 2 percent, and used the median savings of
34 percent for the green buildings comparison. Kats calculated that the NPV of 20 years of energy savings
in a typical green building ranged from $4 per square foot to $16 per square foot, depending on building
type and LEED level of certification. Kats found that “when compared with an ASHRAE 90.1 baseline
building, LEED-certified buildings in the data set reported median savings of 23 percent; for Silver, the
figure was 31 percent; for Gold, 40 percent; and for Platinum, 50 percent” (Kats, 2010, p. 16).
Studies of Energy Use in Federal Buildings
Fowler and Rauch (2008) looked at 12 green buildings owned by GSA located in half of its
national regions. The sample included seven LEED-certified buildings, one LEED-registered building,
one building constructed to meet the Living Building Challenge, and three buildings designed to achieve
energy efficiency. The building sample included six office buildings, four courthouses, and two
combination office/courthouse buildings. Fowler and Rauch measured the actual energy use of these
buildings based on utility bills. They found that on average the 12 GSA green buildings used 29 percent
less energy than the CBECS national average, 29 percent less energy than the CBECS regional average,
and 14 percent less energy than the GSA energy goal for its portfolio of facilities.
In 2010, Fowler et al. studied 22 green buildings in the GSA’s portfolio. The sample included
updated data from the 12 buildings included in the 2008 study and 10 additional GSA LEED-certified
buildings. In all, the study included 8 courthouses, 12 federal buildings (office space), and 2
courthouse/federal buildings. Thirteen of the buildings were LEED-certified, three were LEED-registered
(one of these buildings did not specify the proposed level of certification), while the others emphasized
energy efficiency during the design phase. The methodology used was generally the same. Fowler et al.
found that energy use in the 22 GSA green buildings, on average, was 25 percent lower than the CBECS
national average, 18 percent lower than CBECS regional averages, and 10 percent lower than GSA
regional averages for fiscal year (FY) 2009.
Data were available for 15 LEED-certified buildings. For five of the seven LEED-Silver
buildings, energy use was lower for all three baselines (CBECS regional, GSA target, GSA regional). The
energy use in two LEED-Silver buildings was higher than the CBECS regional average. The LEED-Gold
buildings used consistently less energy than the baseline for all buildings.
Menassa et al. (2012) looked at the energy use of 11 buildings operated by the Naval Facilities
Engineering Command (NAVFAC) that had achieved various levels of LEED certification (three
Certified, five Silver, three Gold) by 2008. The study compared the site energy of the LEED-certified
buildings to 11 NAVFAC buildings of similar size, function, and location that were not LEED-certified.
Menassa et al. found that 7 of 11 LEED-certified buildings reduced their electricity use when compared to
their non-LEED-certified counterparts, with reductions ranging from 3 to 60 percent less electricity.
However, 4 of the 11 NAVFAC LEED-certified buildings used more energy than their non-LEED
counterparts, ranging from 11 to 200 percent more energy. Four of five LEED-Silver buildings used 3 to
49 percent less energy than their non-LEED counterparts, while one LEED-Silver building used 128
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percent more energy than its non-LEED counterpart. Two of the three LEED-Gold-certified buildings
used 6 percent and 15 percent less energy than their non-LEED counterparts, while the third used twice as
much energy as its non-LEED counterpart. Only 3 of the 11 NAVFAC LEED-certified buildings used
less energy than the CBECS national average.
Regional Studies of Energy Use
Turner (2006) looked at measured energy usage (at least 1 year of utility bills) of 11 LEED-
certified buildings (three building types) in relation to initial modeling predictions and to a baseline
approximate to code in the Pacific Northwest. Energy was measured as per conditioned square feet and
savings estimates were made by comparing actual energy to the energy use predicted by models. Turner
found that all of the buildings used less energy than the baseline approximate to code, averaging nearly 40
percent below that baseline. Nine of the eleven buildings achieved energy savings when compared to a
baseline similar building in the region. The author calculated NPV benefits for energy assuming a 25-year
time period, a discount rate of 3 percent, constant use of energy, and energy price increases at the rate of
inflation. Based on those parameters, Turner estimated that the cost savings per year for energy for the
LEED-certified buildings would range from $0 to $26 per square foot, with an average savings of $2 per
square foot when compared to the regional median.
In the Turner study, four LEED-NC-Silver buildings used 39 to 57 percent less energy than their
approximate to code baseline model. The two LEED-NC-Gold buildings for which data were available
used 43 to 86 percent less energy than the baseline approximate to code. For the four LEED-NC-Silver
buildings, Turner estimated that the long-term cost savings would be $7 to $26 per square foot; for the
three LEED-Gold buildings the savings would range from $0 to $8 per square foot.
Baylon and Storm (2008) compared the actual site energy performance of 24 LEED-certified
buildings in the Pacific Northwest to the actual site energy performance of a larger sample of
contemporary buildings constructed to local codes. Most of the buildings in the study had been occupied
for at least 2 years. The LEED buildings in the sample saved 12 percent more energy than the comparison
group. The authors noted that energy codes in Washington and Oregon were more stringent than
ASHRAE 90.1-1999, which was the basis for LEED at that time.
Sacari et al. (2007) compared the predicted energy use (estimated during the preconstruction,
design phase) to the actual energy use (utility bills for electricity and natural gas) in 19 new or renovated
green buildings in Massachusetts compared to buildings designed to the Massachusetts baseline building
code. The sample included 12 schools and 7 other buildings. Sacari et al. found that most of the green
buildings were consuming less energy than a building designed to Massachusetts baseline code, although
they were also consuming 40 percent more energy on average than predicted by design models.
Widener (2009) analyzed the post-occupancy performance and costs and benefits of 25 LEED-
certified projects in Illinois. Most projects were certified under LEED versions 2.0 and 2.1. The sample
included more than six building types certified under different LEED programs (e.g., LEED-NC, LEED-
CI) and at all LEED certification levels. All projects provided at least 1 year of post-occupancy energy
use; 17 of the 25 projects provided “whole project energy use data,” where complete energy data were
provided. The performance of all the LEED-certified buildings was compared to three other data sets: the
Turner and Frankel study published in 2008; the 2003 CBECS; and ENERGY STAR®. Widener found
that the 17 LEED-certified projects for which complete energy data were available used 5 percent less
energy than the CBECS comparison group. Widener also noted that there was a large variation in the
energy performance among projects.
Oates and Sullivan (2012) conducted post-occupancy energy consumption surveys for 25 LEED-
NC buildings in Arizona. The sample included various types of buildings that had been certified under
LEED versions 2.0, 2.1, and 2.2 and that had been in operation for at least 1 year as of October 2009.
Actual energy performance of those buildings as measured by EUI for source and site energy was
compared to CBECS data. The CBECS data were normalized to match the gross square feet weights for
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each building type in the LEED sample. The LEED building sample was also characterized by medium
energy intensity (19) and high energy intensity (6) structures. The authors noted that two buildings
accounted for 40 percent of the total data set’s gross square footage and 51 percent of the gross square
footage in the medium energy intensity subset.
The authors found that the 19 medium-energy-intensity LEED-certified buildings used 13 percent
less energy than the CBECS comparison group. (The high energy intensity subset was not analyzed,
because the sample size was too small.) Of the 19 buildings (both medium and high energy intensity use)
with design and baseline model simulations, only one used less energy than had been predicted in the
design case, and only four used less energy than the baseline simulation.
WATER USE
Six of the studies cited under energy use also studied water use. No studies were identified that
focused only on water use in high-performance or green buildings.
Kats (2010) looked at 170 green buildings across the country. Of these, 119 reported projected
reductions (from models) in indoor potable water use when compared to conventional buildings. The
reductions ranged from 0 percent to more than 80 percent, with a median of 39 percent. Kats also found
that water savings generally increased with LEED level of certification. Kats estimated the NPV benefits
of water savings in typical green buildings ranged from $.50 per square foot to $2 per square foot,
depending on building type and LEED level of certification.
Fowler and Rauch (2008) measured water use for 12 GSA green buildings. They established a
baseline for domestic water use as the base load revealed from monthly water use data. Given these
estimates, the average water use for the GSA green buildings was 3 percent less than the baseline.
Fowler et al. (2010) measured water use for 22 GSA green buildings and found that two-thirds of
the buildings used less water than the GSA baseline, with the average being 11 percent lower. Of the six
buildings with higher water use than the baseline, five had cooling towers or evaporative cooling, two had
exterior fountains in a hot, dry climate, and three had non-typical operating schedules. For five of the
seven LEED-Silver buildings, water use was below the national and regional averages and the GSA
baseline. Two LEED-Silver buildings (one with a cooling tower and one with evaporative cooling) had
significantly higher water use than the average. Two of the three LEED-Gold buildings performed better
than the baselines, but one used significantly more water than the baselines in both the 2008 and 2010
studies.
Menassa et al. (2012) found that seven of nine LEED-certified buildings used by NAVFAC
reduced their water consumption by more than 15 percent when compared to NAVFAC non-LEED-
certified similar buildings. Four of the LEED-certified buildings reduced their water use by 50 to 75
percent. Seven of nine LEED-certified buildings reduced their water consumption between 18 and 72
percent. For the four LEED-Silver buildings for which water data were available, water use was 18 to 61
percent lower than their non-LEED counterparts. Two of the three LEED-Gold-certified buildings
showed water savings of 56 and 60 percent, while the third used 90 percent more than its non-LEED
counterpart.
Turner (2006) compared actual water use to modeled water use and to baseline code buildings in
the Pacific Northwest. When compared to the baseline code buildings, four of the seven buildings were
using 8 percent less water. For the seven buildings for which water use projections (models) were
available, six buildings used at least slightly more water than projected.
Widener (2009) collected data on water use for 12 LEED-certified projects in Illinois. Widener
found a wide range in annual water use and attributed it to individual project size, principal activity, and
occupancy.
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OPERATIONS AND MAINTENANCE COSTS
The committee identified three studies that attempted to compare operations and maintenance
costs for high-performance or green buildings to other baselines.4
A 2008 study by the Leonardo Academy measured operating costs for 11 buildings certified
under the LEED-Existing Buildings (EB) program, each of which had a significant component of office
space. Operating costs included cleaning expenses, repair and maintenance expenses, roads/grounds
expenses, security expenses, administrative and utility expenses. Data for the LEED-EB-certified
buildings were collected and compared to the operating costs in BOMA’s (Building Owners and
Managers Association) Experience Exchange Report, an industry standard. The authors found that “in all
categories of operating costs, more than 50% of the LEED-EB buildings have expenses less than the
BOMA average for the region. Total expenses per square foot of the LEED-EB buildings are less than the
BOMA average for 7 of the 11 buildings” (p. 21).
Fowler and Rauch (2008) calculated aggregate operating costs for 12 GSA green buildings and
compared those costs to industry baselines. The baselines were developed from a number of sources,
including data from BOMA and the International Facility Management Association (IFMA). Aggregate
operating costs included water and energy utilities, general maintenance, grounds maintenance, waste and
recycling, and janitorial costs. They found that, on average, aggregate operating costs were 13 percent
lower than average costs than the industry baselines. However, several of the buildings had consistently
higher operating costs in each category.
Fowler et al. (2010) analyzed operating costs for 22 GSA green buildings using the same
definition of operating cost as Fowler and Rauch (2008). Fowler et al. found that on average, aggregate
operating costs were 19 percent lower for the green buildings than the baseline. Aggregate operating costs
for 17 of the buildings were 2 to 53 percent lower than the industry baselines. Five of the 22 buildings had
higher aggregate operating costs than the baselines, ranging from 1 to 27 percent higher.
INDOOR ENVIRONMENTAL QUALITY AND WORKER PRODUCTIVITY
The committee identified five studies that met its criteria for timeframe, robustness, and
relevancy, and that compared indoor environmental quality (IEQ) and the health and productivity of
workers in high-performance or green buildings to that of workers in conventional buildings.5 It should be
noted that a body of well-designed, empirical studies evaluating various factors related to IEQ in all
buildings is available. However, in keeping with its narrow focus on the statement of task, the committee
only evaluated studies specifically related to IEQ and high-performance or green buildings.
Abbaszadeh et al. (2006) looked at the satisfaction of occupants in green buildings compared to
the satisfaction of occupants in conventional buildings using information from the Center for the Built
Environment (CBE) database. They compared surveys from occupants in 21 green buildings (15 were
LEED-certified and 6 additional buildings were reported as green, based on the receipt of national or local
green building or energy efficiency awards) to CBE surveys from occupants in conventional buildings.
The study focused on occupant satisfaction with thermal comfort, air quality, lighting, and
acoustics. The authors noted that “self-reported productivity scores follow the same pattern as those of
satisfaction—productivity scores are high where satisfaction is high and low where satisfaction scores are
low” (Abbaszadeh et al., 2006, p. 366). Other findings included the following:
4
A study by Miller et al. (2010) looked at operations and maintenance costs for EnergyStar buildings and was
not reviewed by the committee because the Energy Star labeling program was not included as part of the statement
of task.
5
Three additional studies Birkenfeld et al. (2011), Singh et al. (2009), and Cook (2005) analyzed only one or
two buildings each, and for that reason were not included in the review of studies by the committee.
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• On average, occupants in LEED-certified green buildings were more satisfied than occupants
of conventional buildings when it came to thermal comfort, air quality, and overall satisfaction with
workspace and building.
• The mean satisfaction score in LEED-rated/green buildings was significantly higher than that
for conventional buildings (1.47 versus 0.93).
• Occupants in LEED-rated/green buildings were more satisfied with thermal comfort
compared to occupants in conventional buildings (0.36 versus −0.16) and more satisfied with air quality
in their workspace (1.14 versus 0.21).
• Even when considering only conventional buildings that were less than 15 years old, the
mean satisfaction score with air quality was significantly higher for LEED-rated/green buildings (1.14
versus 0.52).
• When including only buildings 15 years old or newer in the conventional category, no
statistically significant relationship was found for the IEQ categories of lighting and acoustics.
Fowler and Rauch (2008) used the CBE questionnaire to survey the occupants of 12 GSA green
buildings. All of the green buildings scored above the CBE median for general occupant satisfaction, with
the average being 22 percent higher than the CBE median.
Fowler et al. (2010) assessed 22 GSA green buildings and also used the CBE questionnaire. They
found that, on average, occupant satisfaction with the green buildings in general was 27 percent higher
than the CBE baseline, except for lighting, where it was the same as the baseline.
Miller et al. (2009) conducted a survey of 154 buildings that were deemed green by virtue of
either an ENERGY STAR® label or LEED certification (any level) to determine if green buildings
provided more productive environments. They gathered data for sick days and self-reported productivity
percentages from building occupants who had moved to a new green building. Some 534 tenant responses
were collected from buildings located across the United States. They found that 55 percent of the
respondents agreed or strongly agreed that employees in green buildings were more productive, while 45
percent suggested no change. They also found that 45 percent of the respondents agreed that workers
were taking fewer sick days than before moving to a green building, while 45 percent found it was the
same as before, and 10 percent reported more sick days (the 10 percent were all in ENERGY STAR®-
labeled buildings).
Baird et al. (2012) sought to determine whether there were any significant differences in the
users’ perceptions of a range of factors concerned with the operation, environmental conditions, control,
and degree of satisfaction between sustainable and conventionally designed buildings.
The set of sustainably designed buildings (defined as either recipients of national awards for
sustainable design or highly rated in terms of their country’s buildings sustainability rating tool(s) or had
pioneered some aspect of green architecture) included 31 commercial and institutional buildings (at least
six different building types) located in 11 different countries. Surveys were gathered from 2,035
occupants. The survey questionnaire and baselines for comparison were from the Buildings in Use (BIU)
database. The comparison sample of 109 conventionally designed buildings was compiled from the BIU
database and included buildings that had been surveyed during a similar time period as the sustainable
buildings were surveyed. Baird et al. (2012) found the following:
• An overall improvement in temperature and air quality in sustainably designed buildings was
statistically significant. The sustainable buildings were perceived to be colder on average in winter but
much the same (still on the hot side) in summer, whereas their air was perceived to be both fresher and
less smelly year round.
• Lighting also showed a considerable and statistically significant improvement in the
sustainably designed buildings when compared to the conventional buildings.
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• No significant difference for noise was found in the sustainable buildings compared to the
conventional buildings. There was a perception of slightly too much noise from various internal sources
(e.g., conversations, telephones) in both samples.
• For the sustainable buildings, all of the factors in the satisfaction category showed a
significant improvement over the conventional buildings. Occupants of sustainable buildings perceived
that they were 4 percent more productive than did occupants of conventional buildings. The improvement
in perceived health among occupants in sustainable buildings (4.25) in comparison to occupants in
conventionally designed buildings (3.29) was also statistically significant.
Widener (2009) found that most of the 21 LEED-certified projects in Illinois were not tracking
health-related benefits. Survey results related to occupant overall satisfaction with building comfort (light
level, noise, temperature, air quality/ventilation) were available for 11 LEED-certified projects. Widener
found that overall, occupant satisfaction was high, with the highest-rated categories being lighting and air
quality/ventilation. The lowest-rated category was temperature.
INCREMENTAL COSTS TO DESIGN AND CONSTRUCT
HIGH-PERFORMANCE BUILDINGS
Studies that seek to compare the difference in design and construction costs, the so-called first
costs, or the “green premium,” between high-performance or green and conventional buildings typically
discuss four different types of costs: (1) the baseline costs of the project itself; (2) the marginal capital
costs of some (but not all) green improvements to the project itself, such as more expensive technologies
or materials, which may be offset by savings in other systems; (3) the soft costs associated with additional
documentation, analysis, and evaluation, such as energy modeling; and (4) the direct costs associated with
third-party certification. Those studies, however, use different methods to define the comparison group.
The different methods result in different types of findings. Some studies are specific in evaluating the cost
of individual green strategies on a given building, in effect using a hypothetical baseline model for the
self-same building, much as energy models do. Studies conducted for the GSA and the Indian Health
Service (IHS) to look at the cost differential between LEED-certified and non-LEED-certified buildings
used this approach (SWA, 2004; IHS, 2006). Caprio and Soulek (2011) looked at the cost-effectiveness of
various energy efficiency improvements in Army standard designs. Others reference building budgets,
asking whether the green project cost more than budgeted or anticipated for the conentional equivalent;
Kats (2010) used this approach. Two studies by Mattheissen and Morris (2004, 2007) used the population
approach, aiming to identify whether the population of green buildings was distinguished by cost when
compared to the building stock in general. The latter approach is typically used in valuation studies that
identify whether green buildings sell or lease for more than the building stock in general. The different
methods for calculating incremental construction costs are valid, but should not be combined.
Matthiessen and Morris (2004) undertook a study with the goal of comparing construction costs
of buildings where LEED certification was a primary goal to the costs of similar buildings where LEED
was not considered during design. The authors studied 93 non-LEED-seeking and 45 LEED-seeking
buildings for which data were gathered from the database of the Davis Langdon Company. All costs were
normalized for time and location to ensure consistency for the comparisons. Among their conclusions
were the following:
• Many projects achieve sustainable design within their initial budget or with very small
supplemental funding; suggesting that owners are finding ways to incorporate project goals and values,
regardless of budget, by making choices.
• There was no statistically significant difference [in cost per square foot] between the LEED-
seeking and the non-LEED seeking buildings. The cost per square foot for the LEED-seeking buildings
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was scattered throughout the range of costs for all buildings studied, with no apparent pattern to the
distribution.
A second report using the Davis Langdon database (Matthiessen and Morris, 2007), compared the
construction costs of 83 buildings seeking LEED 2.1 and 2.2 New Construction certification to 138 non-
LEED-seeking buildings (the samples included five different building types). Findings from the study
were the following:
• Many projects were achieving LEED certification within their budgets and in the same cost
range as non-LEED-seeking projects.
• While there appeared to be a general perception that sustainable design features added to the
overall cost of the building, the data did not show a significant difference in the average costs of LEED-
seeking and non-LEED-seeking buildings.
Kats (2010) found that the owners or owner’s representatives of 170 green buildings reported the
median additional cost was 1.5 percent more to build a green building compared to a conventional
building. The large majority of green building owners reported additional incremental costs between 0
and 4 percent, although the total range was 0 to 18 percent. The author concluded that most green
buildings cost slightly more than similar conventional buildings to construct. Generally, the higher the
certification level, the greater the cost premium, but all LEED levels could be achieved for minimal
additional cost.
Three studies looked at the incremental costs associated with energy efficiency or LEED-
certification of federal buildings. Stephen Winter Associates (SWA, 2004) provided a detailed and
structured review of both the capital and soft cost implications of achieving Certified, Silver, or Gold
LEED ratings for the two building types most commonly constructed by the GSA: a five-story courthouse
and a mid-rise federal office building. The study indicated that there was an inherent degree of variability
to LEED construction cost impacts. However, the authors concluded that many Silver-certified projects
could be built at a cost that was within 4 percent of the cost for a similar non-LEED-certified courthouse
or office building, as well as occasional LEED-Gold-certified projects.
The IHS conducted a study (IHS, 2006) to evaluate the potential cost impacts of achieving a
LEED-Certified or a LEED-Silver certification on its facilities, which are primarily hospitals and other
healthcare-related buildings. Among the study findings were the following:
• Initial capital construction costs (design and construction) would require a 1 to 3 percent
increase in the budget to meet the Certification level and a 3.5 to 7.6 percent increase in the budget to
meet LEED-Silver certification.
• Energy savings over 20 years of operation have the potential to significantly mitigate the
initial capital cost impacts. Given the potential margin of error inherent in these types of calculations and
the uncertainty of future energy prices, life-cycle cost savings may completely offset or even exceed
initial capital costs.
Caprio and Soulek (2011) sought to determine the difference in initial investment (incremental
construction costs) for building energy efficiency enhancements intended to meet federal mandates.
Benefit-cost analyses were conducted for the U.S. Army’s new construction standard designs for FY 2013
for the five most commonly constructed Army building types. The results were based on total energy use
and were modeled, not measured. The authors noted that the study was able to show the energy
effectiveness of a range of efficiency measures, but it was not able to show the cost effectiveness of
individual measures, nor was it able to optimize the designs for the highest energy performance at the
lowest costs. They concluded, however, that (1) significant energy savings were possible for all climates,
and (2) buildings achieving 25 to 35 percent energy savings would yield the maximum energy savings for
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the lowest cost. For buildings achieving 35 to 60 percent energy savings, each increment of energy saved
came at an increasingly higher cost (plug load reduction, small-scale renewable energy, building
orientation, site specific design).
Widener (2009) found wide variation among the 15 Illinois LEED-certified projects that
submitted information on construction costs. Widener concluded that similar to conventional buildings,
the variation in construction costs for the LEED-certified buildings may be attributed to principal building
activity and the individual project’s goals and specifications.
The Kats (2010) finding that the median premium is 1.5 percent, as compared to a notional
budget, is not incompatible with the IHS finding that adding green features to a reference conventional
building results in a premium of 1 to 8 percent, nor is it incompatible with the Matthiessen and Morris
(2004) finding that there was no statistically significant difference between the LEED-seeking and non-
LEED-seeking buildings.
CONCLUSIONS
The committee did not identify any research studies that met its criteria and that conducted a
traditional benefit-cost analysis to determine the long-term net present value savings, return on
investment, or long-term payback related to the use of ASHRAE standards 90.1-2010 or 189.1-2011,the
LEED or Green Globes green building certification systems, or the LEED Volume certification program.
The committee did identify 15 studies that compared the energy use of high-performance or green
buildings to conventional buildings. Those studies incorporated different methods, baselines, types of
buildings, and sample sizes; some applied to large areas of the country, and some were specific to regions
or states. Despite these variations, the 13 studies that measured actual energy used (not modeled energy)
found that high-performance or green buildings, on average, used 5 to 30 percent less site energy than
conventional buildings.
There was also some evidence that high-performance or green buildings used less water than
conventional buildings, with average water-use reductions in the range of 8 to 11 percent.
On a building-by-building basis, however, not all green buildings achieved energy or water
savings in comparison to conventional buildings. Because there was significant variability within sample
sets in terms of the types, numbers, and locations of buildings, the committee could not determine with
certainty why individual buildings succeeded or failed to meet the average. For those studies that looked
at buildings certified at different levels of LEED, the evidence that is available is inconclusive regarding
whether LEED-Silver-certified buildings outperformed LEED-Certified buildings, or whether LEED-
Gold buildings outperformed LEED-Silver buildings.
There was also suggestive evidence that operations and maintenance costs may be lower for green
buildings, but the very limited sample size leaves the analysis results outside the range of certainty. The
three studies evaluated all included utility costs (energy and water) in operating costs, so it is not possible
to determine how significant the other factors were in total operating costs.
Additionally, there was suggestive evidence that high-performance buildings result in
improvements in some aspects of indoor environmental quality (air quality, thermal comfort, and overall
satisfaction with workspace).
Regarding the differences in costs to design and construct green buildings in comparison to
conventional buildings, the studies reviewed used different methods to identify those costs. The results
from the studies indicated that design and construction cost (variously defined) would range from 0 to 8
percent higher for green versus conventional buildings, depending on the method used to calculate the
costs and the type of building.
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