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Understanding Energy Ratings on Windows and Doors

In Scottsdale, AZ where spring is hot and summer even hotter, it is important to shield your home from the dangerous heat. Most often windows and doors are the most vulnerable areas for heat transfer and energy loss. So before you shop for new windows and doors in Scottsdale, AZ, you must understand energy performance ratings. These numbers will tell you whether or not these doors and windows will be a good investment for your home.

Just because windows and doors are approved with a blue and yellow Energy Star label, does not mean they are all created equal. Take a closer look at those stickers and you will see a combination of letters and numbers that tell you exactly how well your windows and doors stand up against harsher temperatures. Don’t know how to read the labels? Well here is what you need to look for:

Reading the Labels on Windows and Doors

The white National Fenestration Rating Council (NFRC) label usually contains five measurements. The most critical are the U-factor and the Solar Heat Gain Coefficient (SHGC). The other three measurements are not as important, but still include information that is useful in choosing new windows or doors. Here is a guide for reading each one of these measurements.

1. U-Factor

The range of this measurement is from 0.20 to 1.20. The better the insulator, the lower the number. This means less cool air escapes your home during those scorching days, and less heat leaves your home on colder nights.

2. Solar Heat Gain Coefficient (SHGC)

This measurement ranges from 0 to 1, and the lower the number the less solar radiation the windows and doors allow inside. For Arizona, you want the lowest possible SHGC number. This will minimize your use of the air condition and cut down on your energy bills.

3. Visible Transmittance

The range for this measurement is again from 0 to 1, and the lower number means less natural light passes through. As such, this number only appears on windows or doors with windows. Rooms with low VT windows will be dimmer, perfect for bedrooms and TV rooms. Those with higher numbers will be brighter, great for the kitchen or living space. In the past brighter rooms often meant hotter rooms as well. That is no longer the case. New technologies in window coatings can allow in more natural light, but still keep the room cool.

4. Air Leakage

This number is expressed in cubic feet per minute per square footage of the window or door. Basically, it shows the amount of air that passes through a window or door frame. The lower the number, the more airtight it is. This number is especially valuable when weighing similar products and you are choosing windows or doors in a windy area.

5. Condensation Resistance

This last measurement ranges from 1 to 100, and the lower the number the greater amount of condensation door or window allows building up on the surface between panes. Moisture on the window is not likely to be a problem in the dry heat, and most Energy Star-rated windows resist condensation well.