How to Choose the Right Energy-Efficient Windows for Your Home

A Northern Comfort salesrep showing a customer some window options.

Where is your home most vulnerable to heat and energy loss, wasting your money and the earth's resources? Windows might not be the first thought that comes to mind, but they're effectively glass-covered holes in your home's structure, so they have the potential to suck huge amounts of energy out of your home. Old and thin windows only make the problem worse.

Replacing old glass with energy-efficient windows can save you money by lowering your energy bill. When heat from your home isn't lost into the outside air, your heater doesn't have to work as hard to keep your home warm, so it uses less energy trying to heat up your home.

Knowing what type of energy-efficient window to buy can be difficult—there are so many options that it's hard to know where to start. Fortunately, the most eco-friendly windows are marked by several key signs that can point you in the right direction when it comes to replacing your windows.

What to Look for in Energy-Efficient Windows

According to the U.S. Department of Energy, the best energy-efficient window will keep your home cool in the summer and warm in the winter. A good way to determine which windows will insulate your home the best is to view their energy performance rating, which differs depending on the climate you live in and how your house is designed.

There are three basic criteria in determining energy performance ratings:

  • Direct conduction is the immediate loss of energy through the glass, glazing, frame, or door. This relates to the U-factor, or the rate at which windows conduct heat: the lower a window's U-factor, the more energy efficient it is.
  • Air leakage occurs around and through windows. A window with a low air leakage rating is more energy efficient than one with a higher air leakage rating.
  • Heat radiation enters the house through the sun. The solar heat gain coefficient (SHGC) is the measurement of the solar heat that enters the house through a window. Windows with higher SHGC ratings collect more heat radiation during the winter, naturally keeping your home warmer. Windows with lower SHGC ratings, in contrast,are better at blocking solar radiation, which keeps your home cooler in the summer. The rating you want for optimum energy efficiency depends on where you live and where the window is on your house.

Triple glazing

Triple glazing (triple glass) is a three-pane window system available for homes that offers special LE coatings and Argon or Kripton Gas—materials used to ensure effectiveness of your windows year round. This installation dramatically affects efficiency within homes because it allows less noise to come in, it keeps homes warmer and it provides significantly less or no condensation issues.

Triple glazing has already become common in some European countries and are soon to introduce standards that will encourage the adoption of triple glazed windows in an attempt to conserve valuable energy resources, and although it is not mandatory in Canada yet—it is a worthwhile investment as it will save you money long-term with heating your home, keeping condensation to a minimum and providing a less noisy environment for you and your family.

The Energy Star program is a voluntary U.S. Environmental Protection Agency program that many international companies participate in. Old windows replaced with Energy Star-certified windows can lower energy bills by 7-15%.

Window Wise is a similar program based in Canada focused specifically on windows. Any window certified by Window Wise has better-than-average energy efficiency, advanced protection against water leakage and air infiltration, and the potential to save you an incredible amount of money.


Our new solid-core RevoCell® Window is made with microcellular PVC (mPVC) containing billions of microscopic cells which gives our new window frame a stronger structure and guarantees better efficiency and performance. All at the price of a regular window. The solid mPVC construction gives the durability and strength of a wood window, with the ease of mainentance of a standard PVC hollow-chamber window. This material is much stronger than traditional PVC because it is made with a solid core compared to the hollow chamber construction used in tradition PVC windows.

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