Tools & Resources

Procedures and Ratings

National Fenestration Rating Council provides procedures for rating window systems that are often required by state energy codes: www.nfrc.org

In order to address the needs of the commercial fenestration industry, NFRC developed a site-built product certification program in 1999 and recently approved a NEW nonresidential rating procedure where component data is utilized for obtaining whole product ratings. This new rating procedure will be piloted during the first two quarters of 2009 and is scheduled for full release the fall of 2009. For the most current information on this break through program visit the following NFRC web page: nfrc.org/scnonres.aspx

For information on the current NFRC Site-Built program, you can download the Site-Built Guidelines at: nfrc.org/documents/Site-BuiltGuidelines.pdf

Computer Simulation Programs

WINDOW 5.0 is a publicly available computer program for calculating total window thermal performance indices (i.e. U-values, solar heat gain coefficients, shading coefficients, and visible transmittances). WINDOW 5.0 provides a versatile heat transfer analysis method consistent with the updated rating procedure developed by the National Fenestration Rating Council (NFRC) that is consistent with the ISO 15099 standard. The program can be used to design and develop new products, to assist educators in teaching heat transfer through windows, and to help public officials in developing building energy codes.

THERM is a state-of-the-art, Microsoft Windows™-based computer program developed at Lawrence Berkeley National Laboratory (LBNL) for use by building component manufacturers, engineers, educators, students, architects, and others interested in heat transfer. Using THERM, you can model twodimensional heat-transfer effects in building components such as windows, walls, foundations, roofs, and doors; appliances; and other products where thermal bridges are of concern. THERM's heat-transfer analysis allows you to evaluate a product's energy efficiency and local temperature patterns, which may relate directly to problems with condensation, moisture damage, and structural integrity.

Optics5 allows the user to view and modify glazing data in many new and powerful ways. Optical and radiative properties of glazing materials are primary inputs for determination of energy performance in buildings. Properties of composite systems such as flexible films applied to rigid glazing and laminated glazing can be predicted from measurements on isolated components in air or other gas. Properties of a series of structures can be generated from those of a base structure. For example, the measured properties of a coated or uncoated substrate can be extended to a range of available substrate thickness without the need to measure each thickness. Similarly, a coating type could be transferred by calculation to any other substrate.

WINDOW 5.0, THERM, and Optics5 have been developed by LBNL and are available over the web:
http://eetd.lbl.gov/btp/software.html

The tools are accepted by NFRC for rating window systems. In some cases, these tools can be applied by NFRC-certified simulators, test labs and inspection agencies to determine ratings for non-standard products.

Daylighting algorithms and tools are described in detail in the International Energy Agency Task 21 Daylight in Buildings publication: "Daylight in Buildings: A Source Book on Daylighting Systems and Components".
See http://eetd.lbl.gov/Bookstore.html under Practical Guides & Tools for Energy Users for "Daylight in Buildings: A Source Book on Daylighting Systems and Components".
For those residing outside of U.S. or Canada, please visit: http://www.iea-shc.org. Download the hyperlinked report 8.9.3 "Daylight Simulation: Methods, Algorithms, and Resources" from the CD-ROM directory.

RADIANCE is a lighting and daylighting visualization tool developed by LBNL and is available over the web:
http://eetd.lbl.gov/btp/software.html
This program can model very sophisticated window systems and complex systems, given BTDF measured data.

Daylighting and Electric Lighting Simulation Engine (DElight) is a simulation engine for daylight and electric lighting system analysis in buildings. The program's origin was the LBNL SUPERLITE program from the 1980s, but the new version has updated the code and added new capabilities. It accepts a bidirectional transmittance distribution function (BTDF) and calculates daylight factors. The program can analyze complex systems, where the daylighting window aperture is treated as a directional light fixture and coupled to the interior space. An exterior radiance model is being developed that takes into account how exterior obstructions modify the BTDF incoming flux.
http://eande.lbl.gov/Task21/DElightWWW.html

DOE-2 and EnergyPlus are public domain programs developed by LBNL and other team members:
http://eetd.lbl.gov/btp/software.html

The DOE-2 program for building energy use analysis provides the building construction and research communities with an up-to-date, unbiased, well documented public-domain computer program for building energy analysis. DOE-2 is a portable FORTRAN program that can be used on a large variety ofcomputers, including PC's. Using DOE-2, designers can quickly determine the choice of building parameters which improve energy efficiency while maintaining thermal comfort. A user can provide a simple or increasingly detailed description of a building design or alternative design options and obtain an accurate estimate of the proposed building's energy consumption, interior environmental conditions and energy operation cost. DOE-2 has been used by national labs, universities, and industry for hundreds of studies of products and strategies for energy efficiency and electric demand limiting. Examples include advanced insulating materials, evaporative cooling, low-E windows, switchable glazing, daylighting, desiccant cooling, cogeneration, gas-enginedriven cooling, cool storage, effect of increased ventilation, sizing of thermal energy storage systems, gas heat pumps, thermal bridges, thermal mass, variable exterior solar and IR absorptance, and window performance labeling.

EnergyPlus is a new-generation building energy simulation program based on DOE-2 and BLAST, with numerous added capabilities. The initial version of the program, EnergyPlus 1.0, was released in April 2001. EnergyPlus includes a number of innovative simulation features - such as sub-hour time steps, built-in template and external modular systems that are integrated with a heat balance-based zone simulation - and input and output data structures tailored to facilitate third party module and interface development. Other capabilities include multi-zone airflow, moisture adsorption/desorption in building materials, radiant heating and cooling, and photovoltaic simulation.

A general list of tools offered by the U.S. Department of Energy are available over the web at:
http://www.eren.doe.gov/buildings/tools_directory/software.html

American Professional and Manufacturer's Organizations

American Architectural Manufacturers Association (AAMA)
www.aamanet.org

American Institute of Architects (AIA)
www.aia.org

American National Standards Institute (ANSI)
www.ansi.org

American Society of Heating, Refrigerating and Air Conditioning Engineers, Inc. (ASHRAE)
www.ashrae.org

American Society for Testing and Materials (ASTM)
www.astm.org

American Solar Energy Society
www.ases.org

Illuminating Engineering Society of North America (IESNA)
www.iesna.org

International Code Council (ICC)
www.intlcode.org

National Fenestration Rating Council (NFRC)
www.nfrc.org

Window and Door Manufacturers Association (WDMA)
www.wdma.com

Canadian and International Organizations

Canadian Standards Association
www.csa.ca

Canadian Window and Door Manufacturers Association
www.cwdma.ca

International Energy Agency www.iea.org/

International Standards Organization (ISO)
www.iso.org

Standards Council of Canada
www.scc.ca

Government, Research, and Educational Organizations

Center for Sustainable Building Research
College of Design
University of Minnesota
www.csbr.umn.edu

Electric Power Research Institute (EPRI)
www.epri.com

Florida Solar Energy Center (FSEC)
www.fsec.ucf.edu

Lawrence Berkeley National Laboratory (LBNL)
Buildings Energy Efficiency
Building Technologies Department
eetd.lbl.gov/r-bldgsee.html

Lighting Research Center
Rensselaer Polytechnic Institute
www.lrc.rpi.edu

National Renewable Energy Laboratory
Center for Buildings and Thermal Energy Systems
www.nrel.gov

National Technical Information Service (NTIS)
www.fedworld.gov/ntis/ntishome.html

Oak Ridge National Laboratory (ORNL)
Building Envelope Systems and Materials
www.ornl.gov/roofs+walls

U.S. Department of Energy's Energy Efficiency and Renewable Energy
www.eere.energy.gov

U.S. Department of Energy
www.doe.gov

U.S. Government's Federal Information Network
www.fedworld.gov