Negatives of window AC units:Unsightly, can be taken out by the tenant, can be pushed out by burglars trying to break in, can damage to window framing (tracks/sills) if not installed correctly, creates condensation that needs to be drained outside, if not installed properly condensation can run inside and cause water damage, requires more cleaning of AC unit and filters, need to match size of AC unit to size of room, requires more than one unit to effectively cover all the living areas, less energy efficient, blocks the view out of the window, makes it more difficult to decorate with window coverings, makes it difficult to use window screens, doesn't fit with the norm of the neighborhood, unappealing to prospective renters, hurts the resale value.

or you can simply mount then in the attic with a drainage hose for the condensation to the outiside of the wall itself.

This is usually caused by condensation.

This is an extremely condensed version, as I literally have a deal under contract at the moment of this writing. 

In my excitement of how well it was going I purchased property # 2 in july of 2018 in 72114 - 3 mos in, the tenant stopped paying and property # 1 went vacant for 5 mos.....Meanwhile property # 2 flooded in may of 2019 ($900) - the roof leaked $600, the tenant left (3 mos vacant) A/C condenser line had to be replaced at property # 1 - $675. 

Its about 20 pages of condensed information on exactly how to contact, present yourself, and speak confidently to brokers.

open up the evaporator coil containment & clean it as well as the condensate tubing.

I think in the San Juan area, because most jobs are here and more condensed population, it is a good idea to invest in rentals and airbnb.

Long story short, tenant who was staying at a waterfront property never closed the balcony door which caused constant condensation and damaged the whole AC system.

We spent nearly a half hour discussing what I'm looking for and I'm trying to condense that into a single post.