I'm living with my grandparents while I'm in school and they rarely run the heater. I'm having to fight them to run it because my bedroom was getting too cold for my snakes despite me running a small space heater (like a mini one used as an individual heater) and wrapping my racks with a blanket (since the rack is an open rack). My room was getting around 68-70*F with my tubs having an ambient temp of 73* which is too cool in my opinion for them. I like to keep the ambient temp 75*F or warmer.This is what has prompted me to purchased a closed rack system to help hold in heat.
I say all that to say, running a heater in the garage won't go over well with them. I'm not even sure a bad "paint" smell will either. I'll take a look into latex paints. At least that will work until I can get me some PVC racks. I mainly wanted something to coat the wood so hopefully the humidity and heat won't warp it too much.