Friday, August 12, 2022


Keeping cool in a spring desert

By Bob Difley

Some snowbirds like to stick it out in the desert until the increasing heat thoroughly thaws out their bones before moving north. However, some spring days can easily reach into the 90s and if you are boondocking, running an air conditioner from your main engine or a generator for hours may not be an option.

There are two effective methods to control your interior heat. One is to buy a roll of heat-reflective, foil backed insulation (available from Home Depot and other building materials or hardware stores) and cut sections to fit your front and side windows that face the sun during midday. Taped up on your windows they will reflect most of the sun’s heat. Open the rest of the windows to allow air circulation.
Another method is to install – if it isn’t already installed – a Fan-Tastic Vent (photo). This vent and fan operates on very low amperage and can run for hours off your batteries without using much juice. Set to the highest speed, the fan will turn over the air in your rig in minutes. During the hottest part of the day, set it to draw the hot air out. During cooler periods in late afternoon, set it to reverse and draw in the cooler outside air.

By monitoring your internal and outside air temperatures, you can close your windows when the outside air is hotter than inside. Then when the outside air cools to below the inside temperature, open all the windows to encourage thorough ventilation replacing the inside hot air.

You can find Bob Difley’s RVing e-books on Amazon Kindle.

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4 years ago

My Fantastic fans only blow air out of the RV. No need to blow air into the RV as when air is blown out, outside air is automatically sucked in through windows, doors or a number of poor sealing areas. It’s called a vacuum.

4 years ago

Shade — real or artificial — is also a solution to desert heat. If there is a way to shade the entire roof of a TT or MH, it minimizes heat build-up which also happens to a lesser extent through windows. I once saw an experimental motorhome that had dual automatic awnings running the full length of the rig in the center of the roof. When deployed, they provided full coverage of the roof and two sides of the motorhome. Of course, it precludes having roof-based solar panels. They roof-based armature of the double awning raised it sufficiently to clear a/c units and satellite domes (not dishes), but killed solar panel use, when awnings deployed. A novel (desperate) idea that never found a manufacturer.
Others have tried lining the roof with water trickle or ultra fine mist thin tube sprayers running on an intermittent cycle, to cool the air and roof. Water is too precious while boondocking, but possible in desert campgrounds with hook-ups. Overspray can be a problem if neighbors too close.
Small trailers have tried setting up high-standing tent rooms — duplicating the benefits of a carport — to keep heat off the rig. But windstorms are unpredictable so, for several of the ideas above, strong gusts make these solutions problematic.
The best solution to keep heat from entering your RV windows is to use **exterior** sunblock screens or covers. They avoid heating the window glass and frame which otherwise radiates back all day into your rig if you are putting Reflectix on the inside of windows facing out. And dual pane window manufacturers often warn about not using internal insulation or radiant energy blockers facing out for fear of stressing the window seals. Better to block sun — with awnings or exterior sun screens — before it reaches windows.

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