What is an NFRC label?
An NFRC label is a standardized rating sticker on window units showing energy performance metrics including U-factor, Solar Heat Gain Coefficient, visible transmittance, and air leakage.
The NFRC (National Fenestration Rating Council) label is a black-and-gold sticker affixed to window units that displays standardized performance measurements. This label allows homeowners and contractors in Connecticut to compare windows objectively across manufacturers and models.
The label lists four key ratings:
- U-factor: Measures how much heat passes through the window. Lower numbers (typically 0.20 to 0.40) indicate better insulation. Connecticut's cold winters make this critical for reducing heating costs.
- SHGC (Solar Heat Gain Coefficient): Indicates how much solar heat enters through the glass, rated 0 to 1. Lower values reduce unwanted heat gain in summer; higher values can help capture winter warmth.
- VT (Visible Transmittance): Rates how much daylight passes through, from 0 to 1. Higher values mean more natural light enters your home.
- Air Leakage: Measured in cubic feet per minute per square foot. Lower ratings mean tighter seals and less drafts.
When shopping for replacement windows, the NFRC label provides the most reliable way to evaluate actual performance rather than marketing claims. Ratings are determined through independent testing at accredited laboratories, making them consistent regardless of where you buy.