Do you have forced air heat with ducting?

No heat and water issues are the only emergencies.  

As we transition to electronic records and the chance of title issues from paper records fades into the decades I hope the heat from reform efforts breaks through to the regulations to create a system that is more optimal.  

It will get interesting this summer as those northern cities heat up. particularly Chicago with the threats of violence already in place..... 

When the tenant turns in keys, we conduct a "safety" inspection within 24 hours to ensure the unit is secure, heat or A/C is adjusted, the unit is vacant, the level of cleanliness, etc.

@John Ellis The water and heat is paid by the landlord for both apartment.

A 110VAC would take too long to heat and would.cost extra in electricity. 

This is the simplest method, but it also means your tenants are more likely to abuse the utilities by leaving windows open with the heat or A/C running, leaving lights on, ignoring the toilet that constantly flushes on its own, etc.3.

In addition, owner loaned us $100,000 at 6% simple interest for one year to make major repairs (installed heat pumps, replaced boiler (for heating water only), replaced some siding and major roof repairs.)We were very clear with each other what we each wanted out of the deal.

It will still be expensive (especially if your heater is gas), but may be cheaper than updating all the gas lines buried in the slab.Yes, converting to electric will be expensive and using electric for heat / hot water is more expensive than gas, but both can be converted in a day or so without tearing up the slab or having the tenants move out.