Insulated 24x24 finished, attached garage in the new house I bought when I moved 350 mi. to be near my granddaughter 2-1/2 yrs ago. It was neither heated or cooled. I moved in, in Sept. Prior to that first winter, I have a ceiling heater so that I could keep it moderately warmed for my machine tools. It had its work cut out for it, as there was a sustained period of about 2-wks. in Dec. with temps around -15-16ļ F.
It had adequate electrical for 110v service, but I needed 220v, so I had circuits added when the heater went in. I have a phase converter for the metal lathe and VFD on the vertical mill, so I didn't need 3-phase run in, even though it is on the poles along my street.
Prior to the first summer, I had a split-system heat pump put in, so now the shop, er, I mean garage... is a pretty even temp of 69-72ļ F. Half is my metal working area with my workbench. Some is storage shelves, some is my granddaughter's play area and some is my woodworking area. Machines are either along the wall on mobile stands or tucked away like my Sawstop Jobsite saw.
If I had to, I could still get my car into the garage. I think I could not open the doors, however.
"Quality is like buying oats. If you want nice, clean, fresh oats, you must pay a fair price. However, if you can be satisfied with oats that have already been through the horse, that comes a bit cheaper."