Motorhome AC in desert

We have an 35 ft. Itasca motorhome with ducted air. We stayed a lot in Palm Springs in April, May and June and the ducted air didn't keep up especially with the temps. reaching the 90's. So my husband temporally added a window air to cool off our motorhome. It helped tremendous.
Just recently we replace one of our fantastic fans with an Atwood air conditioner and tested it out last week in Canyon Lake, Az. We ran both air conditioners and it was nice and cold inside the motorhome.

If you are parked in direct sun, it will be hot. To relieve some of the heat, try opening up the roof vents (heat rises). It will still only be 10-20 degrees cooler, but that is something.

When we were in Phoenix last year, it was 113 degrees. We had no shade but there was a breeze. It felt cooler outside under the awning with the breeze than it did in the rig. So we opened the windows on the breeze side and cranked up the A/C. Got the temps inside down to about 85 while the sun was still high overhead.

If you can find shade from the afternoon sun, do it.

Forget air conditioning. It will prove near useless. Overwhelmed by magnitudes.

You need a swamp cooler. One measuring about three feet square. They are a SNAP to sell when you are finished with it.

The evaporative cooling from such a cooler is worth about TEN roof airs. And no this isn't a joke or exaggeration. The chilled air MUST have exits to outside. Both ends from the middle.

One 10-wheel Crown bus conversion. Two 13.5K roof air units on max. Outside temp 115F in Mojave desert. Inside temp 97F

Fitted one evapoative cooler. Same environment. Inside air temp 82 with AC turned off. I won't mention the utlility savings nor the 100+F in the bedroom heat.

This changes in late summer and early fall when monsoon season arrives. Higher humidity. Evaporative cooling becomes useless.

Yes, fitting a swamp cooler is not inexpensive and it's a bit of a hassle. But keep in mind Casinos with RV parking use swamp coolers for a reason.

Trying to keep a rig cool with AC in such brutal temps would be akin to fighting a brush fire with a water pistol.

From The School Of Hard Knocks

You will be hot

Moved to Tech Issues forum from DIY.