Schedule a Free Consultation



How Low-E Glass Can Keep You Comfortable All Year Long

Glass windows that are poorly insulated are a leading cause of energy loss in a typical home. When it is cold outside, the heated air inside your home can radiate through the glass to the outside, making your furnace or boiler “kick in” more often. At the same time, chilly outside air can “leak” into your home through an ordinary glass pane – even if they are dual pane windows. During the hot, humid summer months, cool, conditioned air can escape while warm air infiltrates.

That’s what makes Renewal by Andersen’s High Performance™ Low-E4 glass such an important part of your new windows’ energy efficiency. With our High Performance™ Low-E4 installed, your windows become an effective barrier against thermal conductivity and energy loss.

Renewal by Andersen’s High Performance™ Low-E4 glass is 45% more energy efficient in summer and 56% more energy efficient in winter as compared to ordinary dual panel glass.* Sounds good, right? Well those numbers weren’t high enough for Renewal by Andersen, so they started to produce High Performance™ Low-E4 SmartSun™ glass, which is 70% more energy efficient in summer and 45% more energy efficient in winter as compared to ordinary dual panel glass.*

What Makes Glass Low-E?

Low-E glass is a way to control the heat being allowed into and out of your home. Low-E is a specially coated glass that allows light to pass through, but controls the “emissivity” of heat energy. Emissivity is a measurement of how readily a material radiates absorbed energy. The lower the emissivity value, the more energy efficient the material.

By blocking heat-generating ultraviolet light and reflecting heat back to its source, the High Performance™ Low-E4 glass in our Renewal by Andersen windows mean you’ll need less heating or air conditioning to keep your home at a comfortable temperature. High Performance™ Low-E4 makes our windows some of the most energy efficient windows in St. Louis homes.

FREE Estimate on Replacement Windows in St. Louis

Draw inspiration for your window replacement project from a leading local expert on replacement windows and doors – Renewal by Andersen of St. Louis. Call us today at (314) 310-3636 to schedule a FREE in-home estimate.

*Values are based on comparison of Renewal by Andersen double-hung inserted window SHGC to the SHGC for clear dual pane glass non-metal frame default values from the 2006 and 2009 International Energy Conservation Code.

Reviews

"Have nothing but great things to say about the window installation done today by John Hutchinson with Renewal by Andersen! He was friendly, personable and professional and did a great job installing. He did a great job of putting down roller pads and tarps with next to zero clean up. Would highly recommend them for any window replacement needed!"

Mark V.
Jun 26, 2025

"We had our new Renewal by Andersen windows installed on June 5th & 6th, 2025 and we LOVE them! The quality, beauty, and functionality are best-in-class! The whole experience from dinner presentation at Lazy River Grill, the initial in-home sales consultation and measurement, the regular communications from the salesman and concierge, and the installation team’s professionalism and skills made the process so seamless. This is the second home we have opted for Renewal windows and doors and have been delighted both times! Thank you Renewal by Andersen STL! "

Jeff C.
Jun 7, 2025

"I had an excellent experience with RbA STL. Our designer, Courtney, was great and the finished product is awesome. The installation was easy and the gentlemen left our home cleaner than they found it upon entering. I would recommend RbA STL - you’ll get tired from their constant contacts, and that’s a GOOD thing!"

Jeramy D
Jun 3, 2025

View All Reviews