Detached Garage Update:

After a bitter cold winter of 2001, I decided to finish the inside of the detached garage by insulating, drywalling and heating it.  This makes is possible to store the cars in the winter above freezing and the heater runs often enough to keep the moisture out.  I installed a 50,000BTU propane furnace to do the job with a 100 gal. propane tank out back.  Works excellent, can bring the garage up 10 degrees in a just a couple minutes making practical to keep it about 50 degrees inside unless I go out there to work on a project.