It does require some kind of power, but if you have A/C and heat then it works off of the one that is not currently pulling power.

Duplexes have more appliances (2 kitchens and two heating/AC units) so that is a disatvantage but a used appliance can be fixed in an hour, a hole in the wall take a lot more time.  

Mechanicals are in good shapeARV: $280k-$300k~$74kish left on the mortgage - 6.75% interest about $890 monthly payment / HOA ~$200 a month / Insurance $35 a month / Taxes $355 per month / Tenant pays Water, Gas Heat. 

I raised the rent to $800 because I was planning to transition the units to paying for their own heat so a lower rent amount was fair.

@John Su tenants typically take care of snow when occupied, but owner is responsible when vacant - and some cities write tickets if snow not removed with x hours.In colder climates you also have to worry about keeping heat on when vacant so pipes don't freeze.

I didn't like that it took half an hour to heat up, meaning I had to think of it in advance.

A house can pass inspection but once someone is living there it's being put under daily stress (faucets turned on/off, heat/AC on an off, etc) so be prepared for repair costs 

Windows are drafty etc and heating through out the house is very Inconsistent. 

So I analyse each property individually, looking at major features like roof, heating, cooling, hot water, anything likely to break down really. 

I've backed out of deals due to roofs and ACs/Heating if I didn't like the inspection report info.