I picked up a Danby air conditioner at Costco for a good price - around $350. It hooks up to the window with a sliding part that customizes to several window sizes. This unit keeps a bedroom nice and cool during the summer, but it is LOUD! I've had mine for about three years and it has started to leak so I keep it in a big Tupperware container. Aside from the leak it works perfectly It even has a remote so that you can adjust the temperature or turn the unit off/on in bed. I would recommend this unit for the price, kind of sad mine leaks though.
I bought this in the winter time (as they are cheaper) and I love it. It keeps my bedroom nice and cool and I have now used it for 5 years and I haven't had an issue with it.
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