A couple of comments I'll share on this. I have gone thru a couple of the kerosene heaters. The newest one, 70k BTU, is much cleaner than previous models...don't know why, but there's very little odor from it. I need something substantial (forced air) to heat my garage as I have high ceilings...they're probably 14'. I can get the temp up high enough and not burn an insane amount of fuel and it doesn't take too long. I make it a point to buy very clean kerosene from the hardware store in gallon or 2.5 gallon jugs. This stuff is quite a bit cleaner than the stuff you'd buy at the gas station and has to be partially resposible for the low odor. If you really want to great crazy, XOM produces a synthetic kero you can find every once-in-a-while at HD, but it's around $8/gallon. There is no odor from this syn product. I only burn a few gallons of kero (probably less than 5) during the entire season.
I've also got a radiant heater that clamps on top of your BBQ tank bottle. While it kicks out a tremendous amount of heat, it's only useful if you're standing at your work bench, for example. It's of little to no value if you're moving around your car.
You can also buy the electric radiant heaters and mount them on a wall and focus it at the front of the car while doing an oil change, etc. Problem is, the throw isn't very far so you've got to be fairly close to it to have any effect. I am thinking about picking one of these up to avoid using the kero heater at all unless I am detailing. I don't like the noise from it and I understand breathing the fumes + CO isn't great for one's health.
Stay warm!