Ok, I have a rental house that up to this point I have never had air conditioning in. The renter could put a air unit in if they wanted one.
*** Had to many stolen by tenants over the years.

I want to put a unit in, the house is about 800 sq ft, a small two bedroom , one bath. It has a fairly open floor plan. I have 220 outlet for a air unit at the window already. What size would you recommend.
And I guess a 220 unit would be preferred over a 110 or two 110 units or would it??

I am down sizing my life and I am going to move into it and sell my home I am living in now.

Keep in mind that it won't cool the entire house with out freezing the living room out first if it is mounted in the living room , so I might suggest a unit slightly smaller then if you were doing the home with central air, Here's my suggestion go with a 18,000 BTU 220 volt unit or two smaller units probably 9,000 BTU's in biggest bedroom and 12,000 BTU"s in living room. You would probably not be running them at the same time but might be entertaining in the living room so need a pinch more here, lets see what every one else has to say, Good luck. Mike

What about energy consumption of the 110 units compared to the 220 units ?

I would suggest 220volts on both if possible.The cheaper to operate.

Fr_Chuck, you might look into a mini split system as well if you go with one system, they are very quiet and can mount up high (out of the way) and can be operated with a remote, and require only a 3" hole in the wall,
Just a thought, Mike

I am not familiar with a "split" system, does anyone have a link to a web site that shows them?

I found one that shows what they look like and prices. HTTP:// Genie air conditioning and heating and airconditioner.com The Largest supplier of room air conditioners in the United States. Over 40,000 units in stock priced to blow out GENIE Air Conditioning GENIEAC and Air Conditioner Directory Air Conditioners MINI_SPLIT
The mini split has an out side condensing unit like central air, the inside is low profile and hangs on wall. Best , Mike