Reading the NFRC label on windows

What is the NFRC sticker?
The NFRC label or sticker is placed on new windows by the manufacturer. The National Fenestration Rating Council (NFRC) is a government ratings agency that evaluates products for their impact on the environment and their ability to increase energy efficiency.

What do the ratings mean?
There are several ratings numbers on the sticker that determine the level of efficiency that the window is designed for. This will help determine your level of energy efficiency savings and helps determine if a window is right for your climate.

What is meant by "right for my climate"?
The United States has several climate zones as I am sure you are aware. Certain plants survive or thrive in specific climates. Some plants need a lot of sun where others are less tolerant. Some (like Napa Valley wine grapes) like the cool foggy mornings and evenings with a hot dry sunny day. For the discussion of windows though, we are talking about the number of heating days versus the number of cooling days in the year.

The Southern States have more days of sunshine and hot weather while our Northern States have a longer winter and a mild summer. In the South, we'll be running the air conditioner more often than the heater. Minnesotan's will be running the heater much more. I have many friends in Seattle that do not even have air conditioning in their home...unheard of in Houston.

So what do the numbers mean?
The two most important numbers to look at are the Solar Heat Gain Coefficient (SHGC) and the U-Factor (UF).

SHGC: A windows ability to keep the heat from the sun out is called the solar heat gain coefficient. Something with full exposure to the sun is the base number of 1. The SHGC number relates to the percentage of solar gain the window can block out. Windows that block out 70% of the solar heat gain have a coefficient number of .30. In the Southern Region, a low solar heat gain coefficient of .30 or lower will help your air conditioner work more efficiently by blocking 70% or more of the solar heat gain from outdoors. Northern clients will appreciate a higher SHGC since it will help them on clear sunny winter days since they will allow the sun to warm the house.

U-Factor: The UF of a window is the number relating to how efficiently the windows insulate your home and keep your heated air in. Again, 1 is the base number and the lower the number, the better an insulator the window is. A UF of around .30 is a good target with lower numbers being better for our Northern neighbors.

This is a lot to remember! Do I have to know this stuff?
When you are dealing with a qualified remodeling contractor, such as All-Tex Exteriors make sure your representative understands your concerns and how important reducing your energy bill is. They can help you arrive at the correct window for your specific needs.