NFRC and Energy Codes
Requirements
for fenestration products (windows and other glazed products)
have been in the building codes for many years. Typically these
requirements had more to do with structural performance and safety
glazing than with energy. However, since the 1970’s, energy
code requirements have been established for windows in both residential
and commercial construction. NFRC’s sole mission is to establish
a fair, accurate, and credible rating system for fenestration
products and to coordinate certification and labeling activities
to ensure their uniform application. NFRC’s rating procedure
is designed to meet the requirement of the Energy Policy Act of
1992 and certain federal government program requirements (DOE,
FTC).
Residential construction is typically defined as one and two family
dwellings; while commercial buildings encompass all else, including
high rise residential, and office buildings, hospitals, dormitories
and the like.
The first commercial building energy
code that was adopted on a widespread basis by many states was
ASHRAE 90.1–89. The first residential building energy codes
adopted by many states were the 1992, 1993 and 1995 versions of
the Council of American Building Official’s (CABO’s)
Model Energy Code (MEC). The Energy Policy Act of 1992 required
states to meet or achieve the requirements of ASHRAE 90.1–89
and to review their existing energy codes to see how they compared
to CABO’s MEC. Since that time, ASHRAE 90.1–99 was
published with significant revisions to the 1989 version. In an
effort to harmonize building codes across the United States, an
International Code Council was formed. As a result the CABO’s
MEC was revised to become the first International Energy Conservation
Code (IECC). The first IECC building energy code was published
in 2000 and included both residential and commercial buildings
requirements.
Note, every energy code provides regulatory, prescriptive, and
system or design requirements.
- Regulatory
requirements include referenced test methods and standards (i.e.,
NFRC), as well as any certification and labeling requirements
- Prescriptive
requirements include the fenestration product minimum performance
criteria (U-factor, Solar Heat Gain) based on climate zones.
In addition, some energy codes provide trade-offs allowing more
fenestration area if these products are more energy efficient.
- System or
design requirements are typically computational approaches allowing
builders and architects to customize buildings and use more
and or different fenestration products and still meet the energy
code requirements through improvements in other areas such as
lighting, HVAC system, or other building envelope components.
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