My criteria would also include the markets I want (I buy properties near my other properties) age of property if that matters, maybe things like the type of heating-cooling etc. 

AirnBn in the mountains will use your heat full blast with a window open for fresh mountain air. 

Cottages in MA means no central heat, is that the same in AL?

This 2 family house has central air and gas heating.

I can give you some general info on insuring a property:Here are some things to look for from an Insurance prospective: Any in-ground tanks (active or inactive)Any Knob & Tube or Aluminum WiringIf built before 1978, does the building have Lead Safe certificationsAny wood stoves or secondary heating units.

We just purchased and househacked our frist duplex at 232,000$ renting out the other side for 1,150$ tenant pays heat and electricity.

The biggest concern that comes to mind is how much of the wiring was replaced if it was exposed to that level of heat...If I place this under contract it would be a cash purchase. 

Eventually you will get tenants that war over the heat or cooling or who drain the hot water leaving the other unit with cold showers.

We have about $5000 worth of electrical work that's partially done, where they were paid in full 60% of that for the rough electrical work and no trim work has been started.The shop is a family multi generational shop named Terpstra Heating and Cooling, that does mostly HVAC but mixes in some electrical as well. 

How old is the heating system?