Lake Havasu used to be hotter than Phoenix, but all the blacktop made them eventually surpass Havasu's heat - you can fry an egg on your car if you don't care about the paint :o). 

We also have all of our tenants pay their own heat and electric. 

There many be some gems to consider there, and the area is a growing hot spot for Phx dwellers escaping the heat for the Summer. 

Not all of our properties have central AC and most tenants will be starting to put out their window AC units in a few weeks when things heat up here in Pennsylvania.  

Basement installation doesn't make a lick of sense IMHO.Just keep the hot tub at the heated setting for winter months.

If it’s a combination heat/ac unit that runs on the older Freon and just the ac needs replacing.

Onr of my rentals origanally had a floor register for the heat with hardwood floors , I made an inlay pattern out of red oak and white oak . the rest of the floor was white oak . it became the center piece of the room . 

You take every item that will need replacement at some point - water heater, AC, heat, appliances, windows, roof, etc.

They had central heat only.

Can be a challenge when heat is needed for contractors, but the right ones bring portable propane heaters.What specific repairs have you had done to the property?