@Nathaniel Walker our heating company suggested that changing the venting of the current tanked water heater from the chimney to direct vent would cost more than installing a new tankless

I would think electric heat would get extremely expensive in NE Wisconsin (but then what do I know).

That can help control the heat if the HVAC system is determined to be working effectively. 

@Joshua Hackathorn - depending on where the duplex is located, the gas bill (assuming it is heating the property) can be very high. 

I live in Miami , where the prices are really high and for the most part , it’s not great for investing .

When a child jumps up and down on the heating vents in the floor to destroy them, pulls out drawers on the floor etc.

I live in Miami. 

I'd have an AC guy check heat and AC and I'd have a peek into the attic to see what kind of wiring I have and if there are any water leaks from the roof.

Overuse of electric can result if the tenant is not using energy efficient lights and appliances, keeping the lights on unnecessarily, using electric heat on with windows open, etc.

@Quinton C.I’m located in Madison, WI - it seems that almost all do not include utilities unless dealing with old properties where they can’t economically be separated such as boiler heat in a 100+ year old building/house.