My Car is in an unheated garage all winter. It's covered with a flannel lined cover. I leave a 25 watt light bulb on an alligator clip (attached to the brake pedal) burning the whole time. I figure it keeps the cockpit area a little warmer than the ambient and thus prevents condensation.
Before I start it I put a 75 watt bulb under the crankcase for a day or so to heat up the
oil.
Bob