A bit of thread drift, but perhaps related to those mulling over a hangar construction project that live in colder climates and studying the comments here for ideas...I bought my already-flying -7 in the dead of an Ohio winter early in 2015.
We did the pre-buy, inspections, etc, in a hangar heated with a floor heating system using a boiler and recirculating water-it was awesome! Single digits outside in the morning, but toasty warm inside, especially while laying on the floor working under the ship. Temps in the 60's in the hangar, so ~50 degree delta between inside and out...and supposedly, also very efficient to operate.
If I were to be building a hangar, or, had an unfloored building that I was converting, it would be at the top of the list. It was soooo nice to be walking around with toasty warm feet as well as to be able to shuck off the heavy boots and wear something lighter and more comfortable to work in.
Rob S.