Honestly, if this was all it did I’d want it. Our house is south facing and the front of the house gets very hot in summer. Windows that effectively limited the amount of heat that could come through would help a lot - even if, as you say, it doesn’t actively cool
Also, not Debian, but https://github.com/cleanroom-team/cleanroom is very a DIY unusable system. I didn’t build (most) off it, but I use it on my daily driver and a couple of other machines.