Facts: Owner listed property at an $85,000 was purchased in 2018 for 41,000 and rehabbed(some) mostly flooring paint and heating and air.  

I would suggest Universal heating and air co.  

Thats why most air BNBs in RSOs have a 21 day limit.

I'm coming off a year and a half of doing renovations to my house myself, with help (from bathroom to kitchen, air ducts to installing windows, tiling to plumbing and electrical).

Plus, development of new attractions underway offers several promising opportunities that remain largely untapped so far.Specifically you should consider Air B n B guest income which could be as much as $200 per night with the right amenities and location. 

Last night we looked at this house and it was from 1953 and NOTHING has ever been replaced except the roof, air conditioner, and water heater.

New appliances, furnace, central air, and roof.

Well, I've been living in this house for quite a year now, and the Landlord is always being disrespectful with us and always taking too much to fix things in this 10 years old house that is falling in peaces , last week our a.c broke, it wasn't getting cold, so we asked him and only 4 days later someone came to "help", and the a.c. was working again for 2 days, and then it got it broke (the air made an explosion sound and there was smoke coming out of my son's bedroom air ventilation) so we turned the a.c. off and open the windows so the burning smell would go away and then we called the Landlord and told him about what happened and that we need it him to call someone to fix it or something, anything.

The house still needs central heating and air.

The unit dial concept is OK if you don't mind having to replace those that disappear as each tenant leaves.Be aware of the thermal o/load if the fans get too hot usually because something is blocking the air circulation.