I installed one. It has a temp gauge and only turn on when it reach a certain temp and turn it off when it gets cool enough. It sits above my kid’s bedroom. You can’t hear it from any other room, but in his room, you’ll hear a hum. It’s not that bad, IMHO. But maybe I’m just more tolerant of noise. It’s only very noticeable in the middle of the night but most of the days, it turns off a couple of hours after the sun goes down, since it’ll be cool enough. Except for the last few weeks when it’s hot all the time. You can install it above a room that are least used if you can. I bought mine at Home Depot. Installation was super easy.
WRT whether it works or not, I think it lower the temp in our up stairs by a at least a few degrees. It used to be very hot during the summer up stairs, but now, it’s just hot.
