I'm sure this thread will get "moved", but I'd recommend trying a 'salamander' or 'torpedo' style kerosene heater. They do smell a little, but not bad... as long as you introduce a small quantity of fresh air. I'd go with a minimum of 55,000 BTU. Ready Heater is a common brand and they work well.
I installed a forced hot air system in my uninsulated 3 1/2 car garage. It works great. If I want it warm very quickly, I use it along with my 55,000 BTU Ready Heater... instant sauna!