How much energy can I save with double glazed windows and doors?

All houses lose heat through their doors and windows. It’s a natural thing. But double glazing keeps your home warmer in winter and cooler in summer – as well as reducing your energy bills. The costs and savings will be different for every home, depending on its size and the quality of the double glazing and frame surrounding it. It’s expected that on a standard house, you can save approximately $200-250 per year with double glazing.

So big picture, say your double glazing lasts you 20 years (although it should last a lot longer) and you’re saving $250 a year. That means you’ll save $5,000 on electricity, over the course of its lifetime.

Energy efficient double glazed windows work like this. There are two sheets of glass with a gap in between, typically about 20mm. This creates a barrier that keeps heat in or out

Energy efficient windows are available in a number of styles and materials. Performance is judged on the following:

  • How well they prevent heat passing through the windows
  • How much light moves through the glass
  • How little air escapes in or out, around the window.

It’s the glass,  the gap between the sheets of glass and the way the window is sealed that is important. Low emissivity (Low-E) glass is the most energy efficient choice for double glazing. It lets the light in but reduces the level of heat that can get out or in.