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What Makes a Window Energy-Efficient?

Don’t underestimate how much heat is gained or lost through inefficient windows. According to the Department of Energy, heat gain and heat loss through windows account for 25% to 30% of residential heating and cooling costs. As such, an energy-efficient home window replacement is worth the investment if you’re looking to lower your electricity bill.

What makes a window energy-efficient?


Insulative Window Frames

An energy-efficient window frame should be able to block heat transfer that can increase indoor temperatures and by extension the strain on your HVAC system. Fiberglass and wood are commonly used frame materials with good insulative capabilities. Renewal by Andersen®, your trusted window installer and replacement company, also offers an exclusive wood-and-polymer composite called Fibrex®, which has excellent insulative capabilities, minimal maintenance needs and is durable enough to withstand a wide variety of climates.

Energy-Efficient Glass

You can assess a window’s energy-efficiency by checking its U-factor and solar heat gain coefficient (SHGC) value. The lower the U-factor, the better a window’s insulative capabilities. The lower the SHGC, value, the less solar heat that enters your home. For homes in temperate and moderate climates, we recommend choosing a window replacement with a low U-factor and SHGC value. Renewal by Andersen’s most energy-efficient glass option is High-Performance™ Low-E4®, which is 56% and 47% more energy-efficient than an ordinary dual-pane glass pane in summer and winter respectively.

Insulated Glazing

Windows with insulated glazing have an air space sandwiched between their glass panes to regulate heat. This space is then filled with an inert gas (usually argon, krypton, or a mixture of both) to create an insulative barrier.


Here’s a tip: look for windows with the ENERGY STAR® label. Only windows that have met the EPA’s stringent performance standards have this label.

Renewal by Andersen® of Memphis offers the best replacement windows on the market. What makes our windows different from the rest? As part of our Signature Service, we customize each and every window according to our customers’ needs and preferences. To schedule a free consultation, call us at (901) 979-4460 or fill out this form.


"Love my new windows from Renewal by Andersen. The installation was seamless. The installers were great and very professional. They also made sure to clean up after themselves. Need windows go with Renewal by Andersen."

Tessica Agnew
Feb 28, 2024

"Our windows were the original ones that were installed when they built the house in 1972. They wouldn't open, they had been painted shut. They were single pane and the glaze was cracked everywhere. I had to put plastic up every year to help keep the house warm at least a little bit. My MIL was surprised that there weren't any panes in the windows. Now she loves it. We have put a film on the windows so we can see out but no one can see in. We are loving it!"

Beverley Collins
Feb 16, 2024

"I love my new windows! The installation crew was efficient, courteous and tidy."

Jeannette Kirby
Feb 21, 2024

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