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Window Energy Efficiency: U-Factor

This is the first in a series of articles dealing with window energy efficiency terminology. Check back for more!

Windows have to undergo multiple tests and meet high standards before they can be truly considered energy-efficient and deserving of Energy Star certification. Manufacturers proudly list their ratings on their products’ NFRC label, but to the average consumer, the labels may look confusing. Who takes the time to understand all those confusing acronyms in detail?

To find the most energy-efficient windows for your home, a good understanding of energy standards and certifications will help you understand what you’re looking for. Let’s start with one common standard for windows: the U-factor.

Confused by all those stickers on the replacement windows at the store? Here’s why understanding your windows’ U-factor is an important step in your shopping process. #CustomWindowsTX Click To Tweet

What is the U-Factor?

The U-Factor refers to how well the window keeps heat inside your home. A low U-Factor means the windows does an excellent job of insulating. This factor tends to be more important in cold climates where a warm interior is necessary, but warmer climates like Houston can also benefit from these types of windows. Their insulation helps keep the inside temperature uniform.

Pro Tip: The U-Factor refers to insulating heat, not blocking light. Windows with a good U-Factor will not make your home darker.

What Contributes to Better U-Factor Ratings?

There are two major factors that can ensure your window has an excellent U-Factor: the materials of the window itself and the gas fill between the two panes. Older aluminum windows transmitted heat easily, but modern improvements on this material render it more inert. Materials such as vinyl, fiberglass, and clad wood resist energy transmission by default. Meanwhile, the gases play an important role too. Argon and krypton, two of the most common gas fillers, are denser than air and help to block the transmission of heat.

Keeping Your Home Comfortable

Not all windows meet high-efficiency standards, so diligent shoppers benefit from a detailed understanding of windows and how they’re designed. The U-Factor is only the beginning. With a detailed understanding of different window factors and their advantages, it becomes easier to choose the right windows for your house.

Contact us to start looking for your new replacement windows.