Thanks Robert, In terms of through the wall, I meant an old fashioned Friedrich -- just a regular air conditioner designed to vent out the back.

I have a 40 year old air conditioner unit working great and one that is 10 years old that is having problems already.

We put a little pump unit in the showers with soap, shampoo, conditioner and then buy those by the gallon.

If there's no ducts installed they have mini split/ductless air conditioners.

Also, the model unit had built-in air conditioner but his unit had big stupid air conditioner. so everything was different than the model unit.and today he said that there was a homeless sleeping at the hallway on his floorso they refused to show him the unit that he already made contract and no one is living, but the unit condition was terrible unlike model unit. is this legal?

I'm referring to the type that is basically an air conditioner that can be reversed and bring warm air into the house.

I do the same for tripped breakers, trouble-shooting a furnace or air conditioner, etc.It's free advice so take it for what it's worth.

That monthly cash flow wouldn't buy an air-conditioner.

If we get outbid at that point, it wasn’t meant to be ours, and it wasn’t a good deal.If you are new to buying houses, be sure to look at the major expense items… The roof, the foundation, the plumbing, the electrical, the air conditioner.  

Be cautious on the expenses though -- very unlikely you will ever approach a 50% expense ratio in Hawaii since there are no heaters, air conditioners, and vacancy is non-existent.