i have one like that in my shop, has an adjustable thermostat on it. set it for 70 degrees or so and it will turn on and off by itself. i also have a propane heater in the ceiling, so between the 2 it normally stays nice.

 

Ive got the john deere AC165 165,000 BTUs for my 30X40 shed and it knocks the chill off very nice. Kerosene works better than diesel because it burns cleaner..