4 Qualities to Look for in Energy-Efficient Windows

Last updated on February 13, 2023

Here are the key things you should look for in new energy-efficient windows for your home. Read on!

Windows complete a home. It helps brighten your interior by allowing natural light in and providing a fantastic view of the great outdoors.

That said, windows don’t just allow light into your home. In particular, older models let cool and hot air out, creating unnecessary energy waste and driving up your electric bills. 

In fact, estimates show that heat transfers via the window are responsible for up to 30% of residential cooling and heating energy use. That’s about USD$1,000 wasted every year. For older, outdated windows, this cost can be even higher. 

If you want to increase energy efficiency in your home, replacing your older window is one of the best solutions. However, how do you choose the best windows with high energy-efficiency ratings? This article shares four qualities to look for. 

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new window frame

The frame is the foundation of any window. And choosing the suitable frame material can impact its ability to retain energy. Some structures are more energy efficient than others. 

The best frame materials should have high resilience to changing temperatures, which can directly impact energy efficiency. Temperature swings can cause contraction and expansion of the frame and glass, which can cause small leaks between the frame and the glass over time. 

Generally, fiberglass frames are your best option since they are highly durable and water resistant. They’re also extremely rigid, so they don’t change with the weather, preventing heat transfers.

Wood window frames are another great option since they are natural insulators, providing higher energy efficiency. Most people avoid this material since it’s expensive and requires high maintenance to prevent warping and mold. 

But you shouldn’t decide on frame materials on energy efficiency alone. Choose one that best fits your environment, durability, home aesthetic, and overall budget.

For instance, you should look for a window frame that fits perfectly with your preferred exterior trim to ensure curb appeal and balance. If you want to know more about window trims, Hardie Boys provide a helpful article. 

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Energy Ratings

energy efficient window

One of the easiest ways to determine the energy efficiency of windows is to look for energy ratings. The Energy Star label attached to windows means that it passes high-efficiency standards, increasing energy savings exponentially. 

That said, this sticker doesn’t tell you much about the quality of the windows. So, consider looking for the energy performance window label from the National Fenestration Rating Council. This international independent body rates windows in specific energy-related performance categories. 

If you can’t find stickers, consider asking the manufacturer about specific standard window metrics to determine their efficiency. These metrics include:

  • U-Factor: This is the insulating value of the window. For the best efficiency rating, look for low u-factor numbers. 
  • Solar Heat Gain Coefficient: This metric determines the amount of solar heat that passes through the glass. A lower number is also preferable for this metric. 
  • Visible Transmittance: It determines how much visible light can pass through the glass. A lower number means less light is allowed and potentially reduces heat transfers. 
  • Air Infiltration: It measures the air passing through the windows. A lower number ensures fewer air escapes. 
  • Condensation Resistance: This category determines the amount of moisture it takes for the glass material to condensate in varying weather conditions. Unlike other metrics, a higher condensation resistance means better energy efficiency. 
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Multiple Glass Panes

window frame profile

Single panes were once the standard for windows. Today, however, the more glass panes you have, the more energy efficient they are. 

As such, a double glass window pane is the minimum if you want to increase your home’s energy efficiency. Meanwhile, triple glass panes are becoming increasingly common to prevent heated air from escaping, especially in colder areas.

Aside from maintaining energy efficiency, multiple glass panes improve soundproofing while increasing the window’s durability. 

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Coatings and Gas Injections

window film

Aside from numerous glass panes, the most energy-efficient windows also have extra coatings and gas injections in between, 

A transparent coating can provide extra insulation while minimizing heat transfers. As mentioned above, a low-E UV coating also helps block harmful sun rays. This reduces the heat entering your home while minimizing damage to your furnishing and upholstery. 

Moreover, gas injections in between glass panes can add further insulation. Generally, most multiple-pane windows have some gas fill. Argon and krypton are non-toxic gases and the more efficient for filling between panes. 

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The Takeaway

Most people don’t recognize the need to change their windows to energy-efficient ones. If you’re done having your money fly out of the window, keep in mind the four qualities discussed in this article the next time you’re shopping for new windows.

Increasing the energy efficiency of your home, one part of the house at a time, can go a long way in reducing your electricity bills and benefitting the environment.

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