You guys are lucky to have heated barns and leave compressors on!
My compressors stay off in my unheated barn until I need it - usually only in the warmer months.
I always seem to find myself living in houses with a small carriage barn, the plight of an "old house nut", and either I or a prior owner has insulated and heated each one in various ways.
The one where I spent my 20's and early 30's was heated with a resistive in-wall heater, which stank of burned sawdust each fall, and the place had no cooling. Since I seemed to be forever working on projects mostly in the hotter months, I spent most of my time out there just broiling in heat... with the constantly-running compressor never helping with that. Trying to do any painting out there with isocyanate-hardened urethanes was always a hassle, with my rigging up various window air conditioners to try to make the climate a little less humid, as best I could.
So when I fitted out my current carriage barn, which I believe dates back to the 1770's addition to this house, I decided I was going to have air conditioning! So I installed a mini split system with a single outdoor unit, and one indoor unit on each of the two floors. It is now my refuge and solace on hot days, I'll go out there to work on projects in the cool space, when it's too hot to work outdoors.
Where I (or more specifically the guy who sized and quoted the system) screwed up, is that the single indoor unit on the first floor is woefully under-sized for keeping the space warm on the coldest days in January and February. It'll keep the space a comfortable 55 - 65F down into the 20's, but it struggles when we get into teens and single digits. I've been meaning to get around to having a second or larger indoor unit installed for years now, but there's always other more urgent projects in the way of making that happen.
