Not sure how long it should take to cool off a room. I have a 350 sq ft room. It cools it to about 71 degrees. I would like it to be cooler. I have room darkening curtains I thought the unit was 13,000 btu the previous one I had was 10,000 however now I see something says 10,000 doe which I'm clueless on. I guess I need a 20000 real btu to get the cool I'd like.