I'm building an in law above my garage 24x28. It'll be mostly used in the summer but will be used on an occasional weekend during winter. I've been looking around for a source of heat that can accomodate my needs. I'm looking at everything except oil. Preferably, I'd like something that could keep the place at 45-50 degrees during the time it's not in use, so I'd like something that I could set a thermostat low. I think propane might be my best option but don't really know what to buy. Looking for any advice.