Originally Posted by DaveSSS

One problem with most garage areas is little or no insulation, so trying to keep the space warm is going to cost a lot of money. When I built my retirement home on a 2 acre lot in Loveland, Colorado, I built a separate 1800 s.f. workshop. I bought an 18’x 9’ garage door with the best insulation that I could find (R-17). I put the standard R-38 insulation above the ceiling. The minimum wall insulation is R-19 and about 70 lineal feet of wall has 18 inches of fiberglass stuffed into a 15" thick wall. The foundation has R-10 foam insulation and there's R-10 foam under the concrete slab floor. I heat the shop with a 92% efficient forced-air furnace, much like the one in my home. My house has better insulation, with R-26 in the first floor walls, R-23 in the basement walls and R-60 in the ceiling. I use a 95% efficient forced-air gas furnace with zone control in the house. My December gas bill was $97, with below average temperatures for the month. About $22 of that is gas for the water heater. The other $75 is home and workshop heating, but I only kept the workshop at 55 degrees, since I haven’t been doing any work out there, lately. I can only guess that it costs about $20 per month to heat the workshop, since the house is 3000 s.f. on the main floor (ranch style) and the same for the basement, that’s mostly finished and heated.