I don’t know much about this sort of thing, hence me asking. I have a detached garage which is currently not insulated and not heated. I’d eventually like to get it at least insulated so that it’s not as cold when working in it in winter. (Before I get it insulated, though, I want to run a set of 220 wires to it, in addition to what is already there, but that’s another story). Right now it is bare studs in the inside. Insulating the walls seems easy enough, but it’s the ceiling I’m wondering about. I imagine most normal people would drywall the ceiling and blow in insulation, but I like having the space between the trusses. I do woodworking on occasion, and when working with 8 foot long boards, it’s nice to have the extra room to maneuver them around. Is there any way of doing insulation up on the underside of the roof itself, and leave the trusses open, or does that not make sense with how the airflow around the soffits work? I imagine for a heated house it would be different, but how about an unheated garage?

Picture of said garage roof for your time.