The deal:Purchase price: $136 100 Down payment: $20 415 (15 %)Closing costs: $2 300 Total cashinvestment: $22 715Monthly costs:Amortization: $200 Interest: $190 Utilities: $220 Insurance: $32 Total: $642I rented it out with Air BnB april - september during 2017 and july-august during 2018.

So now we are putting in an auto vent that goes on with the humidity in the air. 

He said I need to be patient and that he can't do anything until I see visible signs of what's there and it would be hard for him to pin point anything since the apartment was recently renovated and the only problem right now is a strong musty/ mildewy smell.I am going to get a highly recommended HEPA air purifier so the tenant isn't breathting this stuff in. https://www.alencorp.com/products/alen-breathesmar...I'll also call more moisture companies.

Can you be lucky .. of course .. and on the flip side can you be unlucky enough to make you water down/shut off your passion of Real Estate .. absolutely Why i have said what i have said above  (handful of examples):1) You may have break in ownership 1/2/3 generations prior to existing seller (i had break in title  from 1949 or properties were in family for 3 generations but paper work wasn't done so NO ONE cant seller proprieties any more easily unless long drawn litigation takes place)2) You may have federal/other judgement associates with seller SSN which prohibits selling of any property owned by seller and not easy to find via a simple lien search (of yes... seen that a ton and loosing a great deal now for this)3)  Property could have utility/water/sewer/ground/air easement that  may not be easily found by county lien (almost lost quarter million for this reason)Having said above, re framing your question as how you can  delay spending money with Title company while looking for properties and/or getting into negotiating with seller where can you go to look up liens etc knowing you need need spend that money later. 

I am going to move out soon and want to close those vents off completely so only the first floor receives the heat/air.

One item is a window air conditioner mounted over the electrical service.

Looking to buy property in 100k range and air bnb it so pay the mortgage since I’ll be working night shift.

are the air filters being replaced? 

I'm an Air Force veteran (POL! 

That said, neither of us want a long-term renter in our house; we feel odd about someone calling it "home", but we don't mind the prospect of doing an Air-bnb or the like.