I'm looking to keep a couple of windows cooler during the summer heat. I'm debating whether I should tape aluminum foil to the outside of the windows to reflect sunlight or if I should set up EPS (Expanded Polystyrene) boards on the inside. The windows get direct sunlight from around 10 AM to 2 PM. To clarify, I really want to know which method would be more effective in keeping my room cool—reflecting the heat on the outside or insulating it from the inside?
2 Answers
Using something reflective on the outside, like aluminum foil, will do a much better job at keeping the heat out compared to blocking it from the inside. It directly prevents excess heat from getting through the glass into your room. If you can swing it, a good outside solution is definitely the way to go! You could always add insulation inside as a backup too.
Definitely reflect sunlight on the outside for the best results! If you do go for the EPS inside as well, that can help with insulation, but as it stands, reflecting outside is the star of the show. That’ll keep your glass from getting too hot and reduce the heat buildup inside your space.
So, is it really all about that outside reflection then?