Get Local Deals on Windows Now
Describe your window project:
Please choose one of the window project!
Window replacement or installation
Window repair
Your zip code
Please enter zip code!
Please enter valid zip code!

Thermal Windows | Thermal Window Replacement |Thermal Replacement Windows Print Bookmark and Share

Thermal windows are always double- or triple-paned. Thermal replacement windows allow far less heat to escape your home in the winter and less heat to get in during the summer, lowering your fuel bills considerably. Most thermal windows also eliminate the need for painting.

Instantly find quality replacement window companies by completing the information to the right. Take advantage of the stimulus tax credit / rebate of up to $1500 for improvements you make to your home windows today!

Thermal Replacement Windows

Thermal windows are typically two to four times more efficient than older single-pane windows. That means you can expect your winter heating bills to drop, on average, about 20 to 30 percent. The bigger your fuel bills and the draftier your old windows, the quicker your new replacement windows will pay for themselves.

Modern windows rely on a wide array of technologies to achieve a level of energy efficiency as high as five times that of traditional windows. All that technology can be confusing. Terms like "Low-E glass"? and “argon gas�? don't mean much to the average consumer. While you needn't feel overwhelmed by these terms, a basic understanding of thermal replacement window ratings will help you choose the window that's best for you without blindly relying on a sales pitch.

Compare FREE Replacement Window Bids


U Factor Rating

An organization called the National Fenestration Ratings Council (NFRC) has developed a rating system based on the U factor. The U factor is the rating most homeowners look at first, and for good reason. This rating measures the heat-loss that occurs through the window. Most homeowners choose to install thermal replacement windows because of the heat-loss that occurs in the winter with their old windows. Most windows now carry this rating so it's becoming easy to make comparisons. Generally speaking, windows all have a U factor between .2 and 1.3; the lower the number, the better.

Window Type U Factor Ratings

Old metal casement window: 1.3

Good quality single-pane window: 1.0

Good single-pane with storm window: .6

Double-pane with Low-E glass: .4

Triple-pane with Low-E glass: .25

More Thermal Replacement Window Ratings

You don't need to get caught up in two-hour sales pitches that dissect every last technological term, but nor do you necessarily want to run to the simplest answer, either. Many websites out there will tell you to ignore everything but the U factor. If you live in a cold climate, this may be the most important rating, but it's not the only one. If you live in a warmer climate, the solar-heat gain coefficient is probably just as important to your overall window performance. If you live in a humid climate, you may want to consider the condensation resistance rating. These aren't difficult, technical terms. Here's a brief description of common performance ratings that may be important for your replacement window rating.

Air leakage: This rating measures how much outside air will infiltrate through your window installation. Fixed- and awning-style windows are usually the best. The range is typically between .1 and .3.

Compare FREE Replacement Window Bids


Solar-heat gain coefficient: Naturally, this is the exact opposite of the U factor. It measures the windows heat gain during the summer months. It's expressed as a number between 0 and 1 and, again, the lower the number, the better.

Condensation resistance: This rating measures the window's ability to resist the formation of condensation. As ventilation and insulation continues to be geared more toward energy-efficiency, condensation is becoming more and more of an issue in homes. In this case, a higher condensation resistance number is actually better.

Visible transmittance (VT): This window rating has more to do with homeowner preference than superior performance. VT measures the amount of light that is allowed to pass through the window. The higher the number, the more daylight you can expect in your home.

Leave a Comment