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If you’re looking for windows for your home, you’ve likely realized quickly that there’s a seemingly endless number of options out there. When selecting windows for your home, understanding their ratings is key to choosing the right windows for your needs, as their rating can significantly impact energy efficiency, comfort, and cost savings.

Here are key ratings to consider when choosing replacement windows for your home:


The U-factor measures the window's ability to prevent heat from escaping. It is expressed as a number between 0.20 and 1.20, with lower values indicating better insulation. A lower U-factor means the window retains more heat in winter, reducing heating costs. This is especially important in colder climates where maintaining warmth is crucial.

Solar Heat Gain Coefficient (SHGC)

The SHGC indicates how much solar radiation the window allows to pass through. It ranges from 0 to 1, with lower numbers reflecting better blockage of solar heat. A window with a low SHGC is beneficial in hot climates as it minimizes heat gain from the sun, keeping interiors cooler and reducing air conditioning expenses. Conversely, in colder regions, a higher SHGC can help harness solar heat to warm the home naturally.

ENERGY STAR Certification

Windows that earn the ENERGY STAR label meet strict energy efficiency criteria set by the U.S. Environmental Protection Agency. These windows typically feature a combination of low U-factors and optimal SHGC values tailored to specific climates. ENERGY STAR-certified windows ensure high performance, potentially lower energy bills, and environmental sustainability.

Learn More

By understanding these ratings, homeowners can make informed decisions that enhance their home's energy efficiency, comfort, and possibly even overall value. Whether you're aiming to reduce heating costs in the winter or keep your home cooler in the summer, selecting the right windows can make a significant difference. If you’d like to speak with an expert about these window ratings, or to find out how you can have high-performance replacement windows installed in your home, contact Diamond Head Windows & Doors today.

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