Our initial intention was to live there for years and slowly fix it up, as it needs quite a bit of work; think central heat and air, windows, fencing, as well as updates (among other things).

Here's an article on the subject: https://www.washingtonpost.com/lifestyle/home/considering-having-your-air-ducts-cleaned-think-again/2019/01/28/cb5c14b4-1393-11e9-b6ad-9cfd62dbb0a8_story.html

For instance I needed a wall air conditioner picked up and installed while I was on vacation he picked it up and installed it.

That is an $8400 per year increase in gross income, or $84,000 in 10 years and that is how you need to do the math.I don't have to remodel the unit, but it has a 1960's kitchen and bathroom and I like to re-wire the units with an upgraded electric panel, 110-volt smoke detectors and I always install an 18,000 btu air conditioner through a wall (not in a window.

Seems that the new tenants may just be really sensitive to the air in the house. 

Seems that the new tenants may just be really sensitive to the air in the house.

Texas in general is a large economy, i believe Texas has one of the largest air turbine farms in the country. 

The lender I work for uses that in addition to  an Air DNA Report and a reservation detail history. 

I would be happy to help find a good deal and get property set up for air bnb

No provision for forced air, or air conditioning at all.