I have an auto repair facility at my home. My garage is 24 by 65 with a 14 ft ceiling. I use a Miller mobile home furnace, 85,000 BTU,
oil fired, forced hot air to warm up the garage first thing in the morning. The thermostat is turned down all the way at night. At 7AM, I turn the thermostat up to 60, then light the wood stove in the back of the garage. After an hour, the Miller shuts off and that is the last time you hear from that all day. The wood stove takes over from there. I have 2 ceiling fans that drive the heat down, and I use around 150 gal of
oil per year, along with 4 to 5 cord of wood. Not bad when you think that I have the garage heated 6 or 7 days a week. I keep the temp inside around 73 or so all day long, most of my customers are female, and women just love a wood stove.
When I first started off, I used an 18,000btu kerosene wick heater, with a small 30,000 btu "torpedo" heater, also kerosene. I used the torpedo heater first thing in the morning, and the wick heater kept the garage at high 60's to low 70's all day long on just over a gallon of kero. The problem is, that kind of heater is good for low budget, but illegal in a lot of states. It is permissable in NH, however the day of the local gas station selling kero is long gone. Most times you have to drive 20 miles or so to fill up a can. Just food for thought, that is my 2 cents worth.
Tom