I had an electrician over to do some work on my house, and he said he was surprised at how energy-efficient this AC is. We use this one unit to cool a 600-sq-ft space, which is a little bigger than the recommendation, but it works just fine. The app is a little bloated with unnecessary features and advertising, but the wifi connectivity is nice - I can adjust the temperature from the other room, or even if I'm out of the house.