Do you consider a permanent heat source in the shop as a tool? I've been heating in the past with kerosene reddy heaters and just last year bought a propane heater, but I want to install wood heat in the shop....I make my fair share of mistakes and I have a good supply of BTU's just waiting to be used.
Steve, I think that a propane space heater (externally vented) coupled with a wood stove is a great combination. That's what I have. The space heater is on a thermostat that makes sure that the shop does not go down to freezing, then when I go into the shop in the morning I start a fire to warm the place up for comfortable working.