Alright I am in ancient times, I use a coal/wood burning furnace, courtesy of a military auction, paid $10 for the pallet of items. The thing sometimes gets cherry hot but man it takes the cold out of the air.
Some of the newer kerosene heaters can use multi-fuels, like biodiesel, diesel, kerosene, and there are a few others. I use a 40,000 one at my business and it works great. You will get water on your tools, due to rapidly heating up the air it will condense the water in the air onto all your surfaces. A quick an easy fix is to wipe all your tools down with old motor oil so the water does not attack as fast. Also when your air in your space begins to start cooling again, the moisture will again form on surfaces.
Jon