hal

Are you aware of the heat output that this device has?  We installed on inside our air conditioner on another trailer and it was practically useless.  The colder it is out doors, the less effective it is.  The "warmed??" air was barely warm. It was too cold to continue to run it.  I would imagine, that it (and the sun) would drive you out of your trailer if you used it in the Arizona desert in July.  Otherwise ours was a big disappointment.  I would recommend that you obtain a "chill chaser" for this purpose.  They are small heaters in metal boxes (with fan) that measure about 8 or so inches square.  They are truely effective.  Be aware though that some campgrounds charge extra if you use any electrical heater or air conditioner.  We stayed in one in which the owner very unpleasantly informed us if we did use one, we would be evicted from the campground.  Turn it on when you first get up and in about ten minutes you will be turning it off.

Hal