Preface to Purchase – Part 2

Certifications & Labels

3rd Party Certification


NFRC – the National Fenestration Ratings Council measures a window’s tested energy efficiency via its resistance to heat flow (U-value), Solar Heat Gain and Visible Light Transmittance. NFRC ratings reference a window’s quality when brand new.

AAMA – an American Architectural Manufacturers Association Gold Certification is the mark of both initial quality and durability. It shows how well a window will hold up against air and water infiltration over years of use.

Energy Star – a voluntary partnership between the U.S. Department of Energy and the window industry. Windows bearing the Energy Star logo meet minimum requirements for energy efficiency, based on quality and geographic area.

What does the NFRC label tell you?

The NFRC label helps you compare between energy-efficient windows, doors, and skylights by providing you with energy performance ratings in multiple categories.

U-Factor (RED) measures how well a product can keep heat from escaping from the inside of a room. The lower the number, the better a product is at keeping heat in.

Range: 0.20-1.20          Look for: Low numbers

Solar Heat Gain Coefficient (PURPLE) measures how well a product can resist unwanted heat gain, which is especially important during summer cooling season. The lower the number, the less you’ll spend on cooling. 

Range: 0-1       Look for: Low numbers

NFRC also has a condensation rating that is optional for manufacturers to include, so you may or may not see it on the label. The higher the number, the better a product resists condensation. 

Visible Transmittance (GREEN) measures how well a product is designed to effectively light your home with daylight, potentially saving you money on artificial lighting. The higher the number, the more natural light is let in.

Range: 0-1      Look for: High numbers

Air Leakage (BLUE) measures how much air will enter a room through a product. The lower the number, the fewer drafts you’ll experience. 

Range:  ≤ 0.3    Look for: Low numbers

Reference Label below (with colors highlighting definitions above)

Manufacturer’s Certification

Is your window an AAMA Gold-Label product?

All of our products are tested and certified to meet AAMA’s performance standards for air, water and structural load. This ensures quality, strength and durability in all of our windows.