Currently mining with a 9 GPU rig (1.3ZEC/mo @ 900W) in an unfinished room attached to my detached garage. I live in Central Texas, and temps hit 100F regularly in the summer. My electricity comes from wind at about $0.14 per marginal kWh in the tier that my mining bumps me into.
Planning a build out and considering options. The room is about 13' x 7', has a door at one end and two small windows. The room is near the main service panel, which has 200A service to the house. It's a small house so plenty of extra power without needing to upgrade main service.
I work with computers for a living so having a home lab would be nice for other reasons aside from mining, but I wouldn't spend the time or money without mining as the main reason (and as the tax writeoff).
Looking for suggestions about building out the room. It's a detached garage, so there is no AC in the building. I could do a window unit or something more fancy if warranted. I could frame in the walls to insulate. I have the funds to do whatever makes sense financially...more DIY miners, antminer, etc.
http://i66.tinypic.com/2mrim9c.png