Low-e Glass in Primary Sash vs. Storm Window
I’m a window restorer in Cleveland, OH, and am finally working on my own windows. I know much has been said here about low-e glass, but I haven’t quite found an answer to my query.
Would it be more energy efficient to install low-e glass in the primary sash, or in the storm window? Or both?
It would seem to me that on the prime sash, it would reflect more heat back in to the home, but result in a colder interstitial space which might reduce the insulating value relative to if the low-e had been installed in the storm window instead.
If low-e in both is best, should the coating on both prime and storm face into the house, or should they both be facing into the interstitial space as they do in an insulated panel?
Every window is getting the full work down, including new storm windows I’m building, so swapping out glass in the prime sash isn’t a biggie. Our old glass barely has any wave to it and is badly scratched, so we would be sacrificing minimal historic character.
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