Thanks guys, we're going to be putting in a heating only unit in the attic that will have ducts, and I'm thinking of putting in an Aprilaire E100V into the duct system. The 100V has a fresh air ventilation option as well.
I'm interested in people's thoughts about humidity in detached garages without AC in climates similar to ours. I could imagine that in the winter with snow, we could get high humidity in there, but more likely I'm thinking that it'll be pretty humid in the summer. I guess I just don't know what humidity to expect if we were to do nothing at all. Thoughts?