Whether you are designing a new building, completing an extensive refurbishment or just looking to replace the windows in your home with more energy efficient windows then you will be offered the choice of double glazing or triple glazing. But is this a good environmental choice?
Intuition tells us that triple glazing should have a lower carbon footprint. The additional panel of glass in the window provides an extra barrier against the cold air outside. However, this extra layer of glass comes with an additional embodied carbon footprint penalty.
Embodied carbon is the carbon footprint of a material. It considers the amount of carbon dioxide emissions (CO2) that are released to extract, refine, transport and process the materials in the window. To compare the carbon footprint of double glazing versus triple glazing we therefore need to consider both the embodied carbon of producing a window as well as its operational carbon in use. Read more below...
Carbon footprint of windows
The results also reveal a more interesting insight. Frame type is more important than the choice of double glazing or triple glazing. The chart below shows the total carbon footprint over 20 years (embodied carbon + operational carbon). This is the time frame it took for the savings in operation to payback the additional embodied carbon footprint, as below.
Double vs triple glazed windows
Of course carbon footprint is only one factor to consider. Other factors include cost (although many studies indicate that triple glazed windows don’t payback their additional price), thermal comfort and noise. But next time you choose new windows please consider a high performance double glazing unit and the type of frame. In the process you could save a healthy amount of carbon footprint as a result.
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