- Achieving Sustainable Site Design through Low Impact Development Practices
- Aesthetic Challenges
- Aesthetic Opportunities
- Air Barrier Systems in Buildings
- Archaeological Site Considerations
- Balancing Security/Safety and Sustainability Objectives
- Best Practices for Accessibility Compliance
- Blast Safety of the Building Envelope
- Building Integrated Photovoltaics (BIPV)
- Chemical / Biological / Radiation (CBR) Safety of the Building Envelope
- Construction Phase Cost Management
- Cool Metal Roofing
- Designing Buildings to Resist Explosive Threats
- Designing for Organizational Effectiveness
- Electric Lighting Controls
- Energy Analysis Tools
- Energy Codes and Standards
- Energy Efficient Lighting
- Evaluating and Selecting Green Products
- Extensive Vegetative Roofs
- Facility Performance Evaluation (FPE)
- Flood Resistance of the Building Envelope
- Glazing Hazard Mitigation
- HVAC Integration of the Building Envelope
- Indoor Air Quality and Mold Prevention of the Building Envelope
- Life-Cycle Cost Analysis (LCCA)
- Low Impact Development Technologies
- Measuring Performance of Sustainable Buildings
- Mold and Moisture Dynamics
- Natural Ventilation
- Passive Solar Heating
- Planning and Conducting Integrated Design (ID) Charrettes
- Playground Design and Equipment
- Psychosocial Value of Space
- Retrofitting Existing Buildings to Resist Explosive Threats
- Running a Design Competition
- Security and Safety in Laboratories
- Seismic Design Principles
- Seismic Safety of the Building Envelope
- Solar Water Heating
- Sun Control and Shading Devices
- Sustainability of the Building Envelope
- Sustainable Historic Preservation
- Sustainable Laboratory Design
- Sustainable O&M Practices
- The Changing Nature of Organizations, Work, and Workplace
- Therapeutic Environments
- Threat/Vulnerability Assessments and Risk Analysis
- Trends in Lab Design
- UFC/ISC Security Criteria Overview and Comparison
- Using LEED on Laboratory Projects
- Value Engineering
- Water Conservation
- Wind Safety of the Building Envelope
- Windows and Glazing
Measuring Performance of Sustainable Buildings
Last updated: 07-23-2010
There are now many resources available to support the design of more sustainable buildings and to assess the "green-ness" of these designs. As the field of sustainable design evolves, many in the field are thinking about measuring the actual benefits of these designs—the performance of buildings that we consider "green." Numerous projects in the U.S. and other countries are attempting to define the qualitative and/or quantitative measures of sustainability and the data needed to implement and assess these measures. These efforts are important because they will enable us to determine:
- if we are having the impact on human health and the environment we expected, and
- what this achievement is costing or saving.
The purpose of this Resource Page is to provide references for various aspects of performance measurement, and to enable users to learn about what is available in this evolving field. Users are encouraged to email the authors of this Resource Page at email@example.com with additional resources so that the section can be kept up to date.
In addition to the WBDG Sustainable Branch, an excellent overview of the various benefits of sustainable design can be found in "Making the Case for Green Building" in Environmental Building News, April 2005. This article outlines the range of potential benefits that could be the subject of performance measurement studies: first cost savings, reduced operating costs, other economic benefits, health and productivity benefits, community benefits, environmental benefits, and social benefits.
Different users ask different questions about performance and want different information and levels of detail. High level measures provide a quick overall assessment of performance on most critical parameters and enable an organization to report on its overall environmental improvement and the benefits of its sustainable design activities. More detailed measures can explain unexpected results and enable a building manager to check on problem areas or monitor/tune ongoing performance of systems.
A. Challenges of Measuring Performance
Measuring performance is challenging for many reasons.
There are different concepts or definitions of "performance" and, as a result, we are often talking past one another. "Performance" can mean: Does the building, as built, exhibit characteristics that are green or sustainable? Is the building routinely operated and maintained sustainably? Are building upgrades, renovations, reconfigurations sustainable? What are the environmental results of sustainable strategies, in terms of resource consumption and environmental impacts? What are the savings realized from a sustainable building (and costs)? What are other benefits (and costs) of sustainable building (social, health, community, etc)?
Actual vs. Modeled Performance. For some metrics, it is relatively easy to obtain actual performance data. For others, it is more difficult and models or estimations must be used. If models are necessary, it is best to use any relevant available "actual" data when possible, to better reflect operating performance rather than design performance.
Data Availability. In some cases, data to support performance metrics is not available. For example, individual buildings on campuses or military installations may not be separately metered for energy or water use.
Feasibility/Effort Required to Gather Data. In some cases, it might be possible to gather data but it might require more effort or cost than an agency or organization is willing to expend. For example, an agency might not be willing to conduct a survey of users to gather data on commuting or satisfaction with aspects of the building.
Data Quality and Consistency. Even when measured data is available, the reliability of the information may be questionable and the ability to collect the information consistently over a given time period may be difficult. For example, metrics related to operations and maintenance may not be collected in a consistent manner over time depending on the sophistication and reliability of the tracking system being used.
Isolating Effects of Individual Buildings. For some aspects of performance, it is very difficult to determine the impact of a single building as opposed to a development or community. For example, we can measure changes in surface water quality, but then how can we attribute these changes to design and operational aspects of individual buildings?
Benchmarks for Comparison. For performance measurement to be useful, we need to be able to determine the level of performance and how it compares to a more typical building in the same climate, with the same occupancies. This requires the specification of benchmarks. Benchmarks can be a building's performance over time, to measure improvements that result from renovation or changes in operations, or it can be based on external yardsticks such as LEED®, EnergyStar®, or others.
B. Resources for Measuring Performance of Sustainable Buildings
In recent years, building owners and designers, researchers, and others have begun performing studies related to the costs and benefits of sustainable design. Some of these studies attempt to address the full impact of sustainable design, while others emphasize the economic aspects, the environmental impacts, and the social aspects separately. Other differences in the studies include whether or not the data is measured, modeled, or some combination of both, whether the information is based on a single building or multiple buildings and the differences in how the baseline or benchmark is being used.
Table 1 characterizes available studies on key parameters and can be used to identify studies that address questions of interest; brief summaries of these studies as well as links for further information follow the table.
Table 1: Available Studies on the Costs and Benefits of Sustainable Design
Resources Focused on the Financial/Business Aspects of Performance: Making the Business Case
One of the most persistent questions about sustainable design is its cost - does it cost more to build and operate a green building and if so, how much more? How long does it take to recoup these costs in operating savings? Which investments in green design pay back more quickly? What other business benefits are there, such as productivity and user satisfaction?
Green office space.
Photo courtesy of Interface.
- The Costs and Financial Benefits of Green Buildings: A Report to California's Sustainable Building Task Force (PDF 3 MB) by G. Kats, L. Alevantis, A. Berman, E. Mills, J. Perlman, 2003.—In a review of 33 California state green buildings, this report finds that a minimal upfront investment of about two percent of construction costs typically yields life-cycle savings of over ten times the initial investment. The cost data used in the study include energy, water, waste, emissions, operations and maintenance, and productivity and health and were largely derived from conversations with architects, developers, and other key individuals. The cost savings estimates were for the state as a whole rather what the building owners or occupants would experience directly.
- The Business Case for Sustainable Design in Federal Facilities by U.S. Department of Energy, Federal Energy Management Program (FEMP).—This FEMP-sponsored study provides significant financial evidence from an engineering cost analysis of a prototype office building, case studies, and research findings that sustainable design is a smart business choice. Both the 20-page executive summary and the longer resource document provide data and information indicating that sustainable design does not have to increase first costs and yields economic, social, and environmental benefits to building owners and society.
- LEED® Cost Study and LEED® Applications Guide by Steven Winter Associates, Inc. for U.S. General Services Administration.—The LEED® Cost Study defines costs associated with LEED® ratings. Two building types (new construction courthouses and federal building modernization) are modeled against two scenarios for each LEED® rating (Certification, Silver, Gold), identifying differential costs of construction, design, and documentation/submission requirements. GSA LEED® Applications Guide outlines an evaluation process in which the predicted first cost impacts of the individual LEED® prerequisites and credits (developed from the Cost Study) are used as a basis for structuring an overall LEED® project approach.
- Federal Sustainable Building Cost and Performance Metrics, U.S. Department of Energy, Federal Energy Management Program.—Increased interest in the measurement of sustainably design buildings resulted in a FEMP funded effort to develop sustainable building cost and performance metrics and a protocol for the application of these metrics. The intent of this work was to provide a relatively simple method for measuring whole building cost and performance that would generate data that could be used to demonstrate the life-cycle benefits of sustainable design to an audience, primarily, of financial decision makers. The metrics include measurements for the cost and performance impact of water, energy, maintenance and operations, waste generation, purchasing, occupant health and productivity, and transportation. The metrics and protocol are being applied to a set of U.S. Navy facilities where sustainably designed buildings will be compared to similar buildings with more historically typical designs.
For more information:
- Building Cost and Performance Metrics: Data Collection Protocol, Revision 1.0 (PDF 1.23 MB) by K.M. Fowler, A.E. Solana, and K. Spees. Richland, Washington: Pacific Northwest National Laboratory, 2005. PNNL-SA-15217.
- Building Cost and Performance Metrics: Data Collection Field Guide, Revision 1.0 by K.M. Fowler, A.E. Solana, and K. Spees. Pacific Northwest National Laboratory, Richland, Washington, 2005. PNNL-SA-15218.
- Building Cost and Performance Measurement Data (PDF 113 KB) by K.M. Fowler. Portland, Oregon: Greenbuild 2004 International Conference and Expo Proceedings, 2004. PNNL-SA-43119.
- e-Building Investment Decision Support™ (e-BIDS) by Carnegie Mellon University and the U.S. Department of Energy.—Building on their multi-year health and productivity research in BIDS, the Center for Building Performance and Diagnostics (CBPD) at Carnegie Mellon has released a DOE supported e-Bids. This publicly available tool identifies whole building design decisions with the greatest impact on energy as well as health, productivity, or organizational effectiveness, and the research studies that help to quantify the life-cycle value of those investments. An ongoing effort, e-Bids outlines the key whole building design guidelines for high-performance building developed by the CBPD and the Advanced Building Systems Integration Consortium (ABSIC), an industry-government-university consortium, and the cost-benefit arguments available to date for six of these guidelines: daylight without glare, high-performance lighting and controls, individual temperature control through underfloor air, mixed mode conditioning with natural ventilation, commissioning, and cool roofs. For each of these design actions, the CBPD team developed: standard and best practice definitions; guidelines to achieve the best practices; cross sectionals of case studies that demonstrate energy and other business benefits; short summaries of individual case studies; life-cycle cost calculations based on average cost and savings data derived from case studies; and descriptions of the national impact that includes energy plus other benefits as well as emission and energy externalities savings.
- Costing Green: A Comprehensive Cost Database and Budgeting Methodology (PDF 368 KB) by Lisa Fay Matthiessen, Peter Morris, Davis Langdon Adamson, 2004.—This paper analyzes extensive data on building first costs to assess the cost of green buildings as compared to other buildings with comparable programs. The paper looks only at construction costs, since these costs are so important in decisions regarding sustainable design. The authors conclude that many projects achieve their sustainability goals within the initial budget or with a very small increase. The paper also includes a budgeting methodology.
- Green Buildings, Organizational Success and Occupant Productivity (PDF 184 KB) by Judith Heerwagen.—This paper explores the wider context of sustainable design, integrating work from organizational effectiveness and human factors in an effort to broaden our understanding and lay the foundation for future research on the costs and values of sustainable design. At the present time, the conversation is dominated by costs because methods for calculating costs are more highly developed and more readily accepted than methods for assessing benefits and value. A few conclusions:
- First, green buildings are relevant to business interests across the full spectrum of concerns, from portfolio issues (e.g., resale value of property) to enhanced quality of individual workspaces (through improved ambient conditions).
- Second, because the potential influence of green buildings is broad, research on green buildings should address a range of outcomes rather than focusing narrowly on just a few. Outcomes of interest to organizations include workforce attraction and retention, quality of work life, work output, and customer relationships.
- Third, green buildings can provide both cost reduction benefits and value added benefits. The emphasis to date, however, has been on costs, rather than on benefits. The need for more data on value added benefits underscores the importance of studies that focus on these human and organizational factors.
- The Human Factors of Sustainable Building Design: Post-Occupancy Evaluation of the Philip Merrill Environmental Center, Annapolis, MD (PDF 473 KB) by Judith Heerwagen and Leah Zagreus for the U.S. Department of Energy, 2005.—The report summarizes the findings from a study of the Philip Merrill Environmental Center building in Annapolis, Maryland. The building, which houses the Chesapeake Bay Foundation, was the first LEED Platinum building in the United States. The Occupant Indoor Environmental Quality Survey, a widely used building evaluation instrument developed by the Center for the Built Environment at the University of California at Berkeley, was implemented in November 2004, almost four years after the Foundation moved into the new building. In addition to the survey, a series of interviews and discussion groups were held with staff one year after the move into the new building. This report includes a detailed summary of the survey findings with additional clarification of occupant responses gathered from the interviews and discussion groups.
- Life-Cycle Cost Analysis (LCCA) by Sieglinde Fuller. National Institute of Standards and Technology, in WBDG. Updated 2008.—Life-cycle cost analysis (LCCA) is a method for assessing the total cost of facility ownership. It takes into account all costs of acquiring, owning, and disposing of a building or building system. LCCA is especially useful when project alternatives that fulfill the same performance requirements, but differ with respect to initial costs and operating costs, have to be compared in order to select the one that maximizes net savings.
- Occupant Indoor Environmental Quality (IEQ) Survey™ by the Center for the Built Environment, University of California, Berkeley.—Although building occupants represent a wealth of information about how well a building works, they are rarely asked to provide opinions or information on workplace or building issues. Surveys of occupant IEQ satisfaction allow designers, developers, owners, operators and tenants to objectively gauge which building services and design features are working and which are not. In the past, however, paper or telephone-based occupant surveys have been expensive to administer. For this project CBE has developed and implemented a cost-effective, web-based survey with automated, easy to understand reporting. It is currently being implemented in a number of buildings to build up an occupant IEQ database for research and benchmarking.
- Post-Occupancy Review of Buildings and their Engineering (PROBE) by Partners in Innovation.—PROBE (Post-Occupancy Review of Buildings and their Engineering) was a research project which ran from 1995-2002 under the Partners in Innovation (jointly funded by the UK Government and The Builder Group, publishers of Building Services Journal). It was carried out by Energy for Sustainable Development, William Bordass Associates, Building Use Studies and Target Energy Services. PROBE studies include a review of design intent and site documentation, technical survey (walk-through and spot checks), energy survey with CIBSE TM22 analysis, envelope pressure test, occupant questionnaire survey, management interviews, designers' response, and publication of the results. This link contains all of the PROBE studies as well as technical papers on methodology, critiques and reviews, and other materials.
- Workplace 20·20 by the U.S. General Services Administration.—The WorkPlace 20·20 program, established in 2002, is currently testing federal workplaces that have been developed by integrated teams of strategic consultants, organizational scientists, designers, and researchers. Although the clients and contexts vary, the teams work from a common approach. They derive design concepts and solutions from a grounded understanding of the organization, its goals, its current and desired work practices, and the current and emerging work styles of its employees. Each of the current workplace projects is being tested pre and post on a wide array of outcomes developed around the Balanced Scorecard (BSC).
- 2007 The Cost of Green Revisited, Lisa Fay Matthiessen and Peter Morris, Davis Langdon, 2007.
Resources Focused on the Environmental Aspects of Performance
Buildings affect all aspects of our environment—air, rivers and streams, soils, plants and animals, oceans—the visible and invisible network of life on the planet. Reducing the damage caused by buildings—and ultimately creating buildings that are net contributors—is an important goal of sustainable design. As noted under social, health, and community measures, it is often challenging to measure actual effects of a single building.
Most information currently available on building performance is contained in case studies that report on strategies incorporated in the design and some actual results, generally energy and water savings. The High Performance Buildings Database, described below, is one resource for such case studies.
One specific type of measurement is environmental life cycle assessment (LCA), a compilation and evaluation of the inputs, outputs, and the potential environmental impacts of a product system throughout its life cycle. This "cradle to cradle" (or cradle to grave) approach is often suggested as a framework for performance measurement that provides a broader, more comprehensive perspective instead of a focus on only one aspect of performance. LCA can address individual building products, assemblies or systems, or whole buildings. It is different from life-cycle costing (see Financial/Business Aspects of Performance section).
Standardized Metrics and Procedures for Building Energy Performance, Lighting System Performance, Photovoltaic System Performance, and Source Energy and Emissions from Energy Use in Buildings
Energy consumption in buildings can have the largest environmental impact of any aspect of the building. The energy performance of buildings can be defined in many ways, which can lead to different conclusions. The Performance Metrics Project (PMP) at the National Renewable Energy Laboratory (NREL) is a U.S. Department of Energy (DOE) commercial buildings research activity whose goal is to standardize the measurement and characterization of building energy performance. This project produced standard performance metrics and procedures for determining building energy performance, lighting system performance, PV system performance, and source energy and emissions from energy use in buildings. Another source of standard of building performance measures is ASHRAE Guideline 14, which presents a detailed description of procedures for measuring and reporting energy and demand savings geared toward retrofit applications.
In-Depth Case Studies of Energy Performance of Six High Performance Buildings by U.S. Department of Energy, National Renewable Energy Laboratory.
An example of comparison graphs available in the NREL studies
The National Renewable Energy Laboratory (NREL) conducted detailed studies of six buildings to document their actual performance and to understand the issues that affected the performance levels achieved. Post-occupancy evaluations began with extensive building monitoring for at least one year; energy flows established from the measured data were used to calibrate building models for energy simulations of performance. Summaries of this study and lessons learned can be found at:
- Evaluation of the Energy Performance of Six High-Performance Buildings: Preprint (PDF 507 KB) by P.A. Torcellini, S. Pless, D.B. Crawley. 2005. 11 pp. NREL Report No. CP-550-38080.
- Lessons Learned from Field Evaluation of Six High-Performance Buildings: Preprint (PDF 716 KB) by P. Torcellini, M. Deru, B. Griffith, N. Long, S. Pless, R. Judkoff, D.B. Crawley. 2004. 16 pp. NREL Report No. CP-550-36290.
The more detailed studies of each of the six buildings, including methods and metrics used, are available as follows:
Chesapeake Bay Foundation's Philip Merrill Environmental Center, Annapolis, MD
- Analysis of the Design and Energy Performance of the Pennsylvania Department of Environmental Protection Cambria Office Building (PDF 2.37 MB) by M. Deru, P. Torcellini, M. Sheffer, A. Lau. 2005. 85 pp.; NREL Report No. TP-550-34931.
- Analysis of the Energy Performance of the Chesapeake Bay Foundation's Philip Merrill Environmental Center (PDF 2.94 MB) by B. Griffith, M. Deru, P. Torcellini, P. Ellis. 2005. 145 pp. NREL Report No. TP-550-34830.
- Building for Environmental and Economic Sustainability (BEES)—Developed by the NIST (National Institute of Standards and Technology) Building and Fire Research Laboratory with support from the U.S. EPA Environmentally Preferable Purchasing Program, BEES measures the environmental performance of building products by using the life-cycle assessment approach specified in ISO 14000 standards. All stages in the life of a product are analyzed: raw material acquisition, manufacture, transportation, installation, use, and recycling and waste management. Economic performance is measured using the ASTM standard life-cycle cost method, which covers the costs of initial investment, replacement, operation, maintenance and repair, and disposal. Environmental and economic performance are combined into an overall performance measure using the ASTM standard for Multi-Attribute Decision Analysis. BEES Please solicits data from manufacturers on their products for entry into the BEES database.
- Energy Design and Performance Analysis of the BigHorn Home Improvement Center (PDF 2.09 MB) by M. Deru, P. Torcellini, S. Pless. 2005. 120 pp. NREL Report No. TP-550-34930.
- Energy Performance Evaluation of an Educational Facility: The Adam Joseph Lewis Center for Environmental Studies, Oberlin College, Oberlin, Ohio (PDF 2.73 MB) by S.D. Pless, P.A. Torcellini. 2004. 155 pp. NREL Report No. TP-550-33180.
- Evaluation of the Energy Performance and Design Process of the Thermal Test Facility at the National Renewable Energy Laboratory (PDF 2.69 MB) by P. Torcellini, S. Pless, B. Griffith, R. Judkoff. 2005. 144 pp. NREL Report No. TP-550-34832.
- Evaluation of the Low-Energy Design and Energy Performance of the Zion National Park Visitor Center (PDF 3.35 MB) by P. Torcellini, N. Long, S. Pless, R. Judkoff. 2005. 156 pp. NREL Report No. TP-550-34607.
- Green Building Challenge, International Initiative for a Sustainable Built Environment—Green Building Challenge (GBC) is an international effort that has involved over 20 countries to develop a sustainable building assessment system, GBTool, tailored for adaptation and use in countries around the world. GBTool addresses site selection and planning, energy and resource consumption, environmental loadings, indoor environmental quality, functionality, long term performance and adaptability, and social and economic factors. Initially developed for assessment of buildings as designed, the 2005 version of GBTool includes criteria for four phases—predesign, design, construction, and operations, which focuses on actual performance.
- High-Performance Buildings Database by U.S. Department of Energy, National Renewable Energy Laboratory.—The U.S. Department of Energy supported the High Performance Buildings (HPB) Database to help improve building performance by showcasing examples of green buildings and providing a standardized format for displaying performance results. DOE also seeks to standardize methods for reporting building performance by collecting data on topics such as energy, materials, indoor environmental quality, and land use. The HPB Database presents information at various levels of detail. An "Overview" level describes key information, including a project's function and most significant green features. More detailed information about the project is separated into a series of modules on process, performance, and results.
- ISO Sustainability in Building Construction, ISO TC 59 SC 17—The International Organization for Standardization (ISO) establishes voluntary standards that are used around the world. Over the past decade, ISO has, for example, established standards for LCA that form the foundation for most LCA efforts in the U.S., and other countries. Currently, ISO is working to establish methodological frameworks for assessment of the environmental performance of buildings and for environmental product declarations. This work is not complete and draft materials are not available to the public, but progress on these documents can be obtained from the ISO website.
- LCA into LEED Projects—The U.S. Green Building Council is working with stakeholders and LCA experts to consider whether and how LCA should be incorporated into its LEED rating system. Work groups are addressing goal and scope, methodology, and tools to ensure a rigorous and practical approach. Results of the project will be available through the USGBC website.
- LEED for Existing Buildings, U.S. Green Building Council—LEED-EB includes prerequisites and credits based on building characteristics (e.g., availability of public transportation), policies/ procedures and documentation that they were implemented (e.g., exterior maintenance/ landscaping), actual performance (e.g., reduction in commuting frequency through telecommuting), and modeling and calculations (e.g., stormwater reduction). LEED-EB addresses issues related to site, energy, water, materials, and indoor environmental quality.
- U.S. Life-Cycle Inventory (LCI) Database by National Renewable Energy Laboratory, Athena Sustainable Materials Institute.—The U.S. Life Cycle Inventory (LCI) Database is a public/private endeavor managed by the National Renewable Energy Laboratory (NREL) and the Athena Sustainable Materials Institute, supported by a variety of Federal agencies, and carried out by BuildingGreen. LCI is a "cradle to grave" accounting of the energy and material flows into and out of the environment associated with producing a material, component, or assembly and is main input to a life cycle analysis. The primary objective of this project is to create and maintain a publicly available LCI database for common unit processes. It is expected that the database will support the expansion of LCA and the development of simplified LCA tools to help us answer many of the environmental impact questions.
Resources Focused on the Social, Health, and Community Aspects of Performance
This is the least studied and least understood aspect of building performance. In fact, we have not clearly defined the parameters to be included. It is often challenging to measure actual effects of a given building on social, community, and health indicators. Note that many of the studies included under Financial/Business Aspects of Performance also include parameters related to human health and well-being, which also relate to this category.
- Sustainable Measures and Guide to Sustainable Community Indicators by Maureen Hart.—This website presents indicators for measuring sustainability of communities: ways to measure how well a community is meeting the needs and expectations of its present and future members. It explains what indicators are, how indicators relate to sustainability, how to identify good indicators of sustainability, and how indicators can be used to measure progress toward building a sustainable community. It also presents lists of potential indicators and data resources.
Using the Results of Performance Measurement
As noted in the Introduction, performance measurement can be used for a wide variety of purposes. Two examples follow. In the first example, an in-depth assessment of energy performance is used to improve the performance of the buildings studied and to understand how energy performance can be improved in future buildings. In the second example, metrics were developed and are being applied for a "whole building" performance evaluation of sustainably designed buildings.
- In-Depth Case Studies of Energy Performance of Six High Performance Buildings by U.S. Department of Energy, National Renewable Energy Laboratory.—Commercial buildings account for 18% of U.S. energy consumption and this number is increasing, primarily because floor area is increasing and the life span of buildings exceeds 30 years. Energy consumption will continue to increase until buildings can be designed to produce more energy than they consume. Based on this conclusion, DOE's Building Technologies program has established a goal for marketable zero-energy buildings (ZEBs) by 2025.
To provide information needed to achieve this goal, the National Renewable Energy Laboratory (NREL) studied six buildings in detail to understand the issues related to the design, construction, and operation of the current generation of low-energy buildings. Post-occupancy evaluations began with extensive building monitoring for at least one year; energy flows established from the measured data were used to calibrate building models for energy simulation performance.
Although all of the buildings achieved energy savings, none of the buildings performed as well as expected. NREL's detailed analyses identified some of the reasons for the actual performance levels and enabled some of the buildings to take steps to improve their performance. In addition, the study led to a greater understanding of factors that affect our ability to achieve energy performance goals. For example, daylighting was less successful than anticipated and peak energy demands were greater, due to such factors as cloudy conditions during peak demand reducing PV effectiveness. Expectations for occupant behavior were optimistic. In one building, the energy consumption was considerably higher than models during the design process predicted. The study was able to determine the cause of the problem so that the owner could take appropriate remedial steps.
Some of the key conclusions of this exercise include the following:
- Owners drive the desire for low-energy buildings
- Setting measurable goals is crucial for achieving low-energy buildings
- Many decisions are not motivated by cost
- Today's technologies can substantially change how buildings perform
- An integrated approach to building design is the best way to lower energy use and cost
- Energy-efficient buildings can be constructed in a variety of climates
- We can replicate the ideas and techniques from these buildings into other commercial buildings
- Evaluation of the Energy Performance of Six High-Performance Buildings: Preprint (PDF 507 KB) by P.A. Torcellini, S. Pless, D.B. Crawley. 2005. 11 pp. NREL Report No. CP-550-38080.
- Lessons Learned from Field Evaluation of Six High-Performance Buildings: Preprint (PDF 7.16 KB) by P. Torcellini, M. Deru, B. Griffith, N. Long, S. Pless, R. Judkoff, D.B. Crawley. 2004. 16 pp. NREL Report No. CP-550-36290.
- Measuring the Performance of Navy Facilities, U.S. Navy, Pacific Northwest National Laboratory.—Since 1998, the U.S. Navy's Naval Facilities Engineering Command (NAVFAC) has had a policy for incorporating sustainable design principles (PDF 228 KB) into new building construction. The policy also states it is the intent of NAVFAC to accomplish this within the given budget constraints and while meeting customer requirements. The hurdle of a building's first cost has been one of the biggest challenges for integrating sustainable design into projects at the Navy. Although considerable progress has been made, to make the next leap in progress the Navy needs to provide actual cost and performance data for their sustainably designed buildings to demonstrate the benefits they are reaping for the investments being made.
To accomplish the goal of providing actual data on sustainably designed Navy facilities, the metrics developed through the FEMP Sustainable Building Cost and Performance Metrics project are being used on seven Navy building sets (see Table 2 for summary of metrics). Each building set includes one sustainably designed building and a similar building on the same Navy site designed in a more 'conventional' fashion. In addition to using the conventionally designed building for comparison, industry benchmarks and existing Navy data will be used when available. The building types that are included in the project are office buildings, barracks, and fitness centers.
Table 2: Building Cost and Performance Metrics for Navy Facilities
Site and building characteristic data (e.g., size of building, number of occupants, etc.) were collected in order to normalize the performance data for analysis. Meters and data collection systems needed to be put in place for some of the buildings. The building cost and performance data will be collected for a minimum of 12 months. The data from these buildings will be used to calculate a return on investment for the sustainably designed facilities, to identify opportunities for individual building performance improvement, and to develop design guidance on the sustainable design techniques that appeared to be contributing the greatest to the buildings' performance.
To date the project has involved identifying the target buildings, identifying the current metering capability, and collecting site and building characteristics data. The first challenge for the project was identifying which sustainbly designed buildings in the Navy portfolio would be the best candidates. Having buildings that were occupied for more than 6 months and identifying a 'matching' conventionally designed building at the same site with the same function proved to be significant limiting factors. Once the buildings were selected the challenge was to clearly identify the metering needs, which have been greater than expected, and to gather the site and building characteristics for each building. Once the building meters are in place, the collection of monthly performance data will begin.
Questions about this project can be directed to:
|Dennis O. Talton, R.A.
Special Assistant for Architecture and Accessibility
Sustainable Development Program Manager
Naval Facilities Engineering Command, Atlantic
|Kim M. Fowler
Senior Research Engineer
Pacific Northwest National Laboratory
PO Box 999 K6-10
Richland, WA 99352
Building / Space Types
Applicable and relevant to all building types
Products and Systems
Building Envelope Design Guide
Federal Green Construction Guide for Specifiers:
Operations and Maintenance
Sustainable and High Performance Building Strategies Research:
- Assessing Green Building Performance: A Post Occupancy Evaluation of 12 GSA Buildings—Case Study (PDF 11.2 MB), Sponsored by: U.S. General Service Administration (2008)
- Assessing Green Building Performance: A Post Occupancy Evaluation of 12 GSA Buildings—White Paper (PDF 828 KB), Sponsored by: U.S. General Services Administration Public Buildings Service, Office of Applied Science Applied Research (2008)
Energy Efficiency Research:
- Energy Savings and Performance Gains in GSA Buildings: Seven Cost-effective Strategies (PDF 4.2 MB), Sponsored by: GSA Applied Research Program (2009)
- Quick Start Guide to Increase Data Center Energy Efficiency (PDF 943 KB), Sponsored by: GSA Applied Research Program and DOE Federal Energy Management Program (2008)
- American Center for Life Cycle Assessment
- American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE)
- High Performing Buildings, a magazine directed to the entire building community published quarterly with actual building case studies.
- Proposed Standard 189.1, Standard for the Design of High Performance, Green Buildings Except Low-Rise Residential Buildings, developed by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) in conjunction with the Illuminating Engineering Society (IES) and the U.S. Green Building Council (USGBC). The standard is slated to be the first code-intended commercial green building standard in the United States when published early in 2010.