Coming next will be a normal house attic fan, this blows about 1320 CFM and costs about $80. I compared this to the fantastic fan that everybody raves about, that costs $280 and does about 350 CFM. The fan will be a little tricky to install under the trailer, in the same space directly under the a/c unit. It will also have its own little closing hatch, to keep the cold air out when not in use. The fan has a switch where it can come on between 50 to 120 deg automatically, I will also install an on / off switch & maybe a timer - there is a similar set up in my house now. I figure at 25% of the cost and 400% more air flow, how can one go wrong? Time will tell !!