Though our house is centrally air conditioned, out guest room is a the end of the vent run, over a garage in facing the sun and thus doesn't get cool enough during very hot days. Our 14 year old granddaughter was coming to spend a few weeks with us and we wanted her to be comfortable. After researching the matter we decided on the ARC-101 for the 200 square foot room. We and she are quite pleased. Worked perfectly.