Triple glazed windows are the new stars of window energy efficiency... but why should you care? Comfort. Comfort is the reason you will want to use triple glazed windows. Before we get too far on why you should be excited about energy efficiency and comfort, here is a brief history of US windows. In the 1930’s, double glazed window technology came to the US. Over the following 20 years double glazed windows were expensive and popularized simply as the peak of luxury and sophistication. Then the global energy crisis hit in the 1970’s, and spurred the full adoption of the much more energy efficient double glazed windows. Flash forward to today and you can easily see our cultural push for sustainability and energy efficiency. We want to save our climate, but not if it hurts too much… Guess what, triple pane windows are more expensive and often only used on sophisticated and luxurious homes. Shocking, I know! Sure, if you have an old leaky house that allows un-tempered exterior air to freely exchange with conditioned interior air at the rate of a cinematic fan, then triple glazing is not going to help you much. But for new homes being built today, triple glazing is a no brainer and let me tell you why.
Let’s get a bit nerdy. U-values are used to compare energy performance of windows, similar to how R values of roofs, walls, and floors measure heat transfer over time. According to www.homebuilding.co.uk, windows with a single pane of glass have a U value over 5. Double glazing is in the range of 1.6 to 3, while PassivHaus standards for triple pane windows are down below 0.8. In fact most of the windows we specify for our northern latitude clients are in the 0.11 to 0.18 range!
Think about your personal comfort when sitting next to a window. Do you get chilled quickly? Here is what happens to the indoor surface temperatures based on various glazing types when it is 32°F outside and an interior room temperature of 70°F:
- Next to a single glazed window, the internal surface temperature is around 34°F.
- Next to a double glazed window (~2000), the surface temperature was around 52°F.
- Next to a modern, energy-efficient double glazed window, the surface temperature is 61°F.
- Next to a triple glazed window with a center pane U value of 0.125, the temperature is 69.2°F
As you can see, double glazed windows are vastly better than single pane windows. Even modern double glazed windows are performing fairly well but the triple glazed window is holding onto heat much better. You used to be able to stand near a window to get a good idea of how warmly you were going to need to get dressed before going outside but those days are gone with triple glazing. Just think how nice it would be at a winter restaurant window seat without your coat on! Super high efficiency triple glazing will make a difference to your heating bills, but the biggest thing you will notice is how comfortable it is in your home, even when right next to the windows and that is something worth getting excited about!