Yes, pretty much what I pay, I have the tank filled once a year, for the shop, 40x60 with a loft pretty much what you have. I did spend a lot for insulation in the walls and ceilings for sure, but it pays off in the long run. Here the tank is free if you buy the gas from them. The heat is almost instant and I can set the minimum temp easy enough. Most of all its a peace of mind, knowing the garage is being heated with least amount of worry and effort......
