NFRC (National Fenestration Rating Council)


What are NFRC 100 and NFRC 200?


NFRC 100 is a set of procedures and guidelines for determining the U-factors* of windows and doors. NFRC 200 is similar to 100, except it is used to determine the Solar Heat Gain Coefficient (SHGC) and Visible Transmittance (VT) of windows and doors. Both are technical documents intended for use by testing labs and other window and door professionals.

When window and door companies mention that their products are tested or certified to NFRC 100 and 200, it simply means that they have had simulations and/or physical testing performed on their products in accordance with the guidelines published in NFRC 100 and 200.

You can download the actual documents at no charge from the NFRC here.

* "U-factor" is the official term, but "U-value" is often seen in this context. They both mean the same thing.




Thermal Windows, Inc. NFRC-Certified ENERGY STAR® Products


Use the links below to see detailed NFRC Certified Product Directory (CPD) performance information for our ENERGY STAR-qualified residential products.

Series 6600 Single Hung vinyl
Series 6625 Single Slider vinyl
Series 6800 Double Hung vinyl
Series 6825 Double Slider vinyl
Series 6850 Picture Window vinyl




The NFRC CPD program and the U.S. Department of Energy ENERGY STAR program are for residential products only. For commercial window and door energy ratings, the NFRC CMA program is used.


The NFRC's Component Modeling Approach (CMA) Product Certification Program enables whole product energy performance ratings for commercial (non-residential) projects. Performance data from the three primary components that make up a window or door are used to obtain overall product performance ratings. The three primary components used are:

The Component Modeling Approach Software Tool (CMAST) is then used to combine these components and model them to produce simulations that generate U-factor, Solar Heat Gain Coefficient (SHGC), and Visible Transmittance (VT) performance values.


For specific U-factors, SHGC and other data on our products, please contact us at (918) 663-7580 or submit your question here.

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