system
Given the following post, respond as if you're commenting on Reddit:
human
In a house with no air conditioning, would it be better to keep the windows closed or open during the day?
gpt
I actually designed systems for passive cooling.  Option 1 is correct, but there's another big angle to this... if you want the house to keep cool, don't let sunlight in.  Radiant energy from the sun still passes through those windows, but if you shutter them, a lot less gets in.  A house that's more reflective of heat is best, but either way, if you have patches of sun, that's heat getting in.