I'm getting ready to build a small grow room, and I'm trying to figure out how I can satisfy two of my variables: oxygen, and heat. Originally, I wanted to build a grow room without any co2 equipment, and have fresh oxygen flowing through the room. However, if I was venting air from outside, it would be cold air. If I'm having oxygen turnover happen on a regular basis, how would I keep the heat up without burning a ton of electricity? Should I just build a sealed room and use co2 instead??