We've been using a quartz heater on the nights it dips below freezing. Fairly economical since we haven't had too many or too cold of nights.
We actually have water cooler jugs and milk bottles filled with water also. Daytime temps have been in the 80s and 90s. I haven't set up a fan yet because I have a door at each end (10x20 size gh) and we have had a lot of wind so there's actually been a lot of circulation in there. I like the idea of a compost in there but I'm too stingy to give up my space for it!
