I was worried about this purchase.  I live in a converted attic, and it is extremely hot.  Last year the conditioner I had could not cool my place off below 80 degrees.  On top of that I have casement windows, so a traditional air conditioner did not fit properly.  Found this one a decided to give it a try.  I am glad I did, it fit perfectly in the window.  And I had cool air all summer.  It was able to reach the temp I set, even when I wanted 67 in my space, and it cycled on and off very well.  The only thing negative is it is a little loud, but not enough to really complain about.  I kept it on low fan speed, and was able to sleep quite well.    Well worth the money I spent on it.