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Somehow I’d thought the voids were usually evacuated but that doesn’t really make sense with the pressure involved. Apparently it is possible to have a vacuum i
by dan-robertson 4y ago
Somehow I’d thought the voids were usually evacuated but that doesn’t really make sense with the pressure involved. Apparently it is possible to have a vacuum inside but uncommon and harder to manufacture (and you need support pillars to separate the panes). https://www.glassonweb.com/article/vacuum-insulating-glass-past-present-and-prognosis https://www.glassonweb.com/article/vacuum-insulating-glass-p...
- HPsquared 4y agoYou'd still have radiative heat transfer, even if there is a vacuum between the panes. For a given budget, you're probably better off adding more regular panes.
- dan-robertson 4y agoAren’t new windows often coated with something opaque to IR, that way they keep heat in during winter and don’t heat up like a greenhouse in the summer?
- HPsquared 4y agoThose are low-emissivity coatings. Very effective in reducing radiative heat transfer. This is why the glass in a vacuum flask is silvered: metals have low emissivity. These coatings aim to have low IR emissivity while still allowing visible light through (IR light gets reflected, instead of absorbed/emitted). My point was only that a vacuum gap is still not a perfect insulator, so it's an economic trade-off.