What is an NFRC label?
An NFRC label is a standardized rating sticker on a window or skylight, issued under the National Fenestration Rating Council's testing program, that lists independently verified energy performance values. It lets buyers compare products on the same basis.
The NFRC label is the official performance sticker placed on fenestration products, including windows, doors, and skylights, that have been rated under the National Fenestration Rating Council (NFRC). The council is a nonprofit that sets the testing and simulation procedures used to measure how a product handles heat, light, and air. Each label reports the results for a specific product line and glazing package, so the numbers describe the unit as it was tested, not a general claim.
The label typically lists these ratings:
- U-factor: how much heat passes through the product. Lower numbers mean better insulation.
- Solar heat gain coefficient (SHGC): the fraction of solar heat that enters the home. Lower numbers mean less heat gain.
- Visible transmittance (VT): how much visible light passes through the glass.
- Air leakage (AL): how much air moves through the product's seams and operating parts under a set pressure.
- Condensation resistance (CR): a rough indicator of how well the surface resists condensation.
For skylights, the SHGC and U-factor values matter most because a roof opening gains and loses heat more directly than a wall window. Florida homes often compare SHGC closely, since summer cooling load is the bigger concern in Citrus County. Ratings on the label are useful for checking that a skylight meets the energy code that applies to your home, and for comparing two products that were tested under the same conditions.
If you are looking for installers who work with these products, you can browse skylight replacement providers in the directory.