Replacing the windows in your home with more efficient and up-to-date windows is an excellent way to reduce your energy costs, and can make your life easier and more comfortable as well. But you are going to want to do your “homework” before making such an important investment in your home. You’ll soon find that there are many conflicting – and sometimes outrageous – claims about the many windows available today. It can be hard to sort through the bogus information to get to the truth.

One of the very first questions you should ask is to “see the label” on any window you are thinking about buying. I don’t mean the price tag, or even the manufacturer’s sticker. The most important label on a replacement window is the one put there by the National Fenestration Rating Council (NFRC), an independent laboratory that measures the energy efficiency of windows and doors. The NFRC label can provide a world of information about the replacement windows you are about to purchase.

“Fenestration” is a fancy word that means “opening” in a structure. The NFRC has set up a sophisticated laboratory to test the performance of windows in terms of energy efficiency. A manufacturer must voluntarily submit windows for testing, and must live by the results, which are printed on an official NFRC label that is attached to each window made under the specifications tested.

If the window company that is pestering you to buy their windows cannot show you the NFRC label on their products, walk away. No NFRC label means the manufacturer was unwilling to submit their windows for testing, and is a sure sign that the quality and performance of the windows is likely to be sub-par. Don’t waste your money – or a minute of your time – on a company without an NFRC label.

When you do find a window company that proudly displays the NFRC label on their products, take the time to read the label to get an idea of what you can expect from the replacement window. Here is the information you will see, and what it means:

The most essential rating of a window’s performance is its U-Factor, which measures the rate of heat flow through a window. The lower the U-Factor, the more energy efficient the window. U-Factor measures the entire window unit, including the glass, frame, sash, and spacers. U-Factor is the only measurement accepted by the U.S. Department of Energy’s Energy Star™ program. U-Factor ratings generally fall between 0.20 and 1.20. The lower the U-value, the greater a window’s resistance to heat flow and the better the insulating value.

Solar Heat Gain Coefficient
Don’t forget that new windows can help keep your home cool in the summer, as well as warmer in the winter. Solar Heat Gain Coefficient (SHGC) measures how well a product blocks heat caused by sunlight. 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 in the house, and the cooler you’ll fee. Plus, your air conditioner will have less work to do!
Visible Transmittance
Visible Transmittance (VT) measures how much light comes through the window. VT is expressed as a number between 0 and 1. The higher the VT, the more light is transmitted.

Air Leakage
The air Leakage (AL) rating shows how “tight” the window is by measuring the flow of air through cracks and gaps. Unless a window frame is fusion sealed and the glass is fully sealed in the frame, air can pass through the window assembly and reduce its effectiveness. The lower the AL, the less air will pass through cracks in the window assembly.

Get the real story behind how new windows can help you reduce energy use and slash your monthly utility bills by calling Hi-Tech Windows toll free at (800) 851-0900. Or visit out website at