Here's my little mining farm under my house. I'm running 5 - S9 (BTC) & 3 - L3+ (LTC). Will be adding 7 more L3+ and 1 - D9 (DCR) once it arrives.
I built a 6'x6' enclosed room with Cold/Hot chambers exhausting out a crawlspace vent hole.
https://imgur.com/a/0eIcZRI