Resource Center

Resources to help you understand our products and how we build them.

Solar Heat Gain Coefficient

Solar Heat Gain Coefficient (SHGC) measures how much heat from the sun is blocked. SHGC is expressed as a number between 0 and 1. The lower the SHGC, the more a product is blocking solar heat gain. Blocking solar heat gain is particularly important during the summer cooling season in hot Southern climates. By contrast, people in Northern climates may want solar heat gain during the cold winter months to lessen the cost of heating the home. read more

ENERGY STAR

In order to apply the ENERGY STAR ® label to products, manufacturers must first test their FENESTRATION products according to NFRC procedures, which include independent testing at NFRC approved laboratories. These tested products bear NFRC labels that provide important information on the Energy Ratings for the products. This information is of little benefit to you IF you are unsure how to interpret the results and are unaware of the needs for your home. The NFRC label provides ratings for U-factor and Solar Heat Gain Coefficient, and Visible Transmittance (required ratings), and may include information on testing for Air Leakage and Condensation Resistance. read more

Health Smart Windows

Protect your family and your home against window condensation by choosing Health Smart Windows® made with Super Spacer® high performance glass. read more

U-Factor

U-factor measures how well a product prevents heat from escaping a home or building. U-factor ratings generally fall between 0.15 and 1.20. The lower the U-factor, the better a product is at keeping heat inside the building. U-factor is particularly important during the winter heating season in colder climates. This label displays U-factor in U.S. units. Labels on products sold in markets outside the U.S. may display U-factor in metric units. read more

Visible Transmittance

Visible Transmittance (VT) measures how much light comes through a product. VT is expressed as a number between 0 and 1. The higher the VT, the higher the potential for daylighting. read more

Air Leakage

Air Leakage measures how much outside air comes into a home or building through a product. Air leakage rates typically fall in a range between 0.1 and 0.3. The lower the air leakage, the better a product is at keeping air out. Air leakage is an optional rating, and manufacturers can choose not to include it on their labels. This label displays air leakage in U.S. units; labels on products sold in markets outside the United States may display air leakage in metric units. read more

Condensation Resistance

Condensation Resistance measures how well a product resists the formation of condensation. Condensation resistance is expressed as a number between 1 and 100. The higher the number, the better a product is able to resist condensation. Condensation resistance is an optional rating, and manufacturers can choose not to include it on their NFRC labels. read more

What are the other options to consider when shopping for windows?

In addition to the NFRC Label, ratings comparisons, and ENERGY STAR, buyers may consider a number of other factors when choosing windows. These include: air infiltration, water infiltration, structural performance, acoustical performance, security performance, product cost, and warranty. Product cost and warranties are issues to be considered when making any major purchase, and this information is available from the window distributor or manufacturer. read more

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