I got one of these from a Canadian neighbor who brought it from Canada many years ago (part of luggage I think), it's very small but low power (I think it is 5000Btu and 500W, 110v), it cools a small room comfortably with little consumption. The only problem for me is that it is a bit noisy and it takes a good 20+ minutes before it really manages to cool a hot room (but I must say it is a hot room exposed to the sun from every angle).
It also sits on the window edge, so half of it hangs out of the window, exposed to the sun and rain, so far so good, but not sure how long it will last.
I use it only occasionally in a hot afternoon/evening, they are mainly replaced by the split systems now, hard to find, but the small ones hardly need any installation, sit on window edge, plug and go, good for occasional use.
Some reviews here:
http://bestreviews.com/best-window-air-conditioners