In a nutshell, performance ratings measure a window's energy efficiency. They tell you how well a certain window will regulate the flow of heat, light and air entering and escaping your home.

Discover the best 5-star window ACs of 2025 offering energy efficiency, powerful cooling, and reliable performance for your ...

STATEN ISLAND, N.Y. -- Replacing your old windows can have a significant impact on your energy costs. When it comes to drafty windows, we naturally think of winter, when the air is cold and drafts ...

Energy efficiency is the main plank of the current EU energy policy. The building sector has become the focus for delivery of energy efficiency targets as it accounts for over 40 percent of energy ...