I bought this during 100+ degree summer heat as my portable window unit had failed. I bought a sleeve and mounted the unit in the wall and it's been working great ever since and it easily holds the temperature below 70 degrees. I'm quite happy with it. The only negatives are: 1. That it often bugs me to clean the filter when an inspection shows the filter to be just fine.  2. Even in cool weather below the set point the unit continues to cycle on every now and then, usually for less than a minute. These items are not enough to prevent my rating it as a great air conditioner that works well.