CW2274 provided the link to his AC fan and he's right. If your setup is at all possible to have an AC fan, then do it. You don't have to worry about clouds moving over the sun, fan voltage dropping, then the cloud moves away and fan voltage rises again (causing possible spikes in your temps). AC fan, completely constant airfow 24/7. No ifs ands or buts. THE way to go, especially in very hot climates. I'll never look back.