Dec 02, 2014
Hello Niles. My solar air heater has a pretty standard drum (not blade) 'squirrel cage' fan. Quiet, and it moves 90 cubic feet a minute. I took a temperature reading last year, at floor and at the top of the faulted ceiling in the living room (14.5 ft), and the temperature difference was only 2 degrees, so it does an excellent job of de-stratifying the air.