[Yukon 400]

I have a 175,000 btu kerosene torpedo heater in the garage, a few weeks ago when it it was 25-28 outside it kept my three car garage a toasty 80 degrees without a problem. They do have open flame and do omit a slight odor depending on what fuel you use in them. If you use diesel which is the cheapest fuel the odor is noticeable, with kerosene it's really not that bad but prices can be high hardware stores here sell it at $9+ a gallon, if you can get it in bulk or a fueling station it should be about half. I've found that if you can get a hold of Jet A at a small airport it's under $5 and hardly any odors.

They do have the propane version of the torpedo forced air heaters, my neighbor has one and they work jut as well, without emitting any odor. But I do believe he spends a lot more on fuel.

If you do get one having a thermostat or even better a digital one saves on fuel costs while maintaining your desired temperature.

I've had a dual head infrared heater that connects on top of a propane tank, it was only good for local heat, they work if you are only in one location. After having a forced air one I would not go back to something that just radiates heat.

The lowest it gets here is the mid 20's so I don't have any experience in colder temperatures.