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Window FAQs

How old are your windows? Do you still feel air coming in when they’re closed? Are they hard to clean or so difficult that you can’t even open them anymore? If you answered yes to even one of these questions, then it’s time to partner with Illinois Energy Windows & Siding, Inc., one of the largest home improvement companies in Chicagoland.

Common Questions About Windows

  • What is Low-E glass? Low-E glass is manufactured by adding microscopically thin, virtually invisible metal or metallic oxide layers to the surface of the glass. Low-E window glass coatings lower heat transfer between glass layers so glass functions more efficiently.
  • What is argon gas? Argon is an inert, non-toxic gas that insulates between window panes so that heat transfer is decreased.
  • What is Solar Heat Gain Coefficient? Solar Heat Gain Coefficient is a measurement of how much solar radiation comes into a building in the form of heat. The lower the number, the better the glazing is at preventing solar gain.
  • What is winter U-Factor? This number represents the rate of heat flowing through a window in winter weather conditions of 0˚F outside and 70˚ inside. The smaller the number, the better the window system is at reducing heat loss.
  • What is the function of the National Fenestration Rating Council? The National Fenestration Rating Council (NFRC) provides third-party certification of window energy performance on an independent basis.

Save With Energy-Efficient Windows From Illinois Energy Windows & Siding, Inc.

Get the peace of mind that comes from knowing that your windows are energy-efficient, well-crafted and will save you money as you heat your home in winter and turn on the air conditioning on those hot summer days. Custom windows designed with SmartGlass365 will bring you many years of enjoyment and enhance your home’s curb appeal.

  • Save money on utility bills with SmartGlass365. Enjoy a delightfully cool house in the summer and more warmth in those cold winter months.
  • Get strong protection against UV rays.
  • SmartGlass365 is easy to clean and dries practically spot-free.

Get Your Free Quote Today

Illinois Energy Windows and Siding offers complimentary quotes for your convenience! Simply fill out our online form or give us a call to get started. We are looking forward to transforming your home one step at a time, starting with beautiful replacement windows!
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What Our Customers Are Saying

Our reputation is built on more than just quality products. From spotless worksites to professional installation teams, our customers share their experiences of how we go above and beyond.

★★★★★

Illinois Energy employees got here right on time and finished the work without any problem. They did the work very efficiently and finished the work on time. They cleaned up the whole thing that we didn't have to do anything after they left. Very satisfied with their work and punctuality.

Jaya Kannankeril
★★★★★

Recently Illinois Energy Windows & Siding did a fabulous job installing a bow window, along with a few standard size windows in our home. The installation crew was quick and did a wonderful job cleaning up after themselves.

Michelle Kerfman
★★★★★

Just had our new windows installed and we're very happy with the quality. The installers were very respectful of our home and property and did a beautiful job with installation and clean up. I even noticed that I hear less noise from outside! Glad we got this upgrade to our home.

Christine Warner-Uginchus
★★★★★

We were so pleased with our experience with our windows and patio door installations. The two Illinois Energy installers arrived on time. They immediately laid tarps and put up plastic shields to contain the dust. They worked efficiently and cleaned up when they finished. We highly recommend them.

mailpost21
★★★★★

Several of our windows have been replaced with windows from Illinois Energy. Installation of the windows went smoothly, furniture was moved, and drop cloths protected our rugs. We were very satisfied with our choice of windows, and the excellent service we received from Illinois Energy.

Lydia Selbka
★★★★★

This review is another review for Illinois Energy Windows and Siding, Inc. I recently had them install a patio door. I was very pleased with the products and excellent customer service. They responded quickly to any questions/concerns I had during the process. Just as before, the installation went smoothly, and the installers arrived on time, explained everything to me and cleaned up thoroughly. I plan to use them again in the future to replace additional windows. I also like the lifetime warranty they offer with their products and service.

Charmaine Allen
★★★★★

They recently replaced 2 half moon windows in my townhome. I had many plants in the front yard near the windows which they were very careful not to destroy. They worked carefully and quickly. I had minimal cleanup when they left. I did not even have to repaint the interior of my house and nothing was damaged as a result of their work. I have used this company before and will use them again.