I would have central air/heating repaired.

Is it a window AC unit or is it a Central air unit?

A high tech air filtration unit, a newer heat/ air unit?

I now understand you were looking for the things that normal due diligence might miss.I had a person who bought a property that was in a larger town and there was the air space above the house that was sold so that no one could block another building or sign. 

Now I'm only getting 3-10 Messages per day.Sometimes people get there and don't like that it's a duplex and they have to share laundry, some don't like that it doesn't have central Air, and some just don't make enough money to qualify or have bad credit.

Our first month as new landlords we had an AC blowing hot air and a broken pipe in the backyard.

We have a small D2 University a good size hospital and an air Force Base.

We finally sealed all the walls, ceilings and floors with Zessner odor killing sealer which helped a lot, purchased an air purifier, and kept the house open as much as we could. 

@Louis SulekBack in the 60s & 70s, I lived in Bellville and Trenton (Carrying Place) and my father lived there during the 80s while he flew out of CFB Trenton.There is enough rotation through the air base, that there should be a firm rental market.

However i'm looking for some insight on an idea that came to me.I just evicted a tenant from one of the nicest apartments in my portfolio and originally thought about personally occupying it, but i move around alot, so i began thinking about air b and b.