Understanding The Information on a Window/Door Sticker

Here is a brief explanation of what all those numbers and codes mean on the NFRC sticker that is on new windows & doors.

NFRC Label

Get a Price

Schedule Your Free In-Home, No-Obligation Quote Today.

  • U Factor Picture


    The rate of heat loss is indicated in terms of the U-Factor. The lower the U-Factor, the better the window insulates. Energy Star approved windows and doors must have a U-Factor that is 0.32 or lower.

    Five Important Variables in Every Insulated Glass Unit

    Type of glass
    Type of Low-E coating
    Type of sealant system
    Type of spacer system
    Its maintenance-free characteristics

    Air Leakage

    Heat loss and gain can occur by air leaking through cracks in a window. The air leakage rating {AL} is the equivalent cubic feet of air passing through a square foot of window area. The lower the AL, the less air will pass through cracks in the window. Select windows with an AL of 0.30 or less.

    Solar Heat Gain Picture

    Solar Heat Gain CoEfficient

    The SHGC is the fraction of incident solar radiation admitted through a window, both directly transmitted and absorbed and subsequently released inward. SHGC is expressed as a number between 0 and 1. The lower a window’s solar heat gain coefficient, the less solar heat it transmits.

    Condensation Resistance

    Condensation resistance {CR} measures how well a window resists the formation of condensation on the inside surface. CR is expressed as a number between 1 and 100. The higher the number, the better a product is able to resist condensation.

    Visible Transmittance

    Visible transmittance {CT} indicates the amount of visible light transmitted through the window. VT varies between 0 and 1. The higher the VT, the more light is transmitted. A high VT is desirable to maximize daylight.

    Schedule a Consultation Today!

    (630) 280-2748


    Arlington Heights

    718 East Rand Road
    Arlington Heights, IL 60004



    815 East Ogden Avenue
    Naperville, IL 60563


    Burr Ridge

    16W240 83rd Street
    Burr Ridge, IL 60527


    learn about our specials

    Learn More