The last week of June 2021 saw an unprecedented heatwave in the Pacific Northwest. Even here in the usually mild oceanside town of Campbell River on Vancouver Island, the temps reached over 100 degrees Fahrenheit. To combat the abnormally extreme heat in a campsite with zero shade, I had to use all my RV cooling tactics.
Our Keystone Cougar fifth wheel is poorly insulated with only 30 amp power input and a single 13.5K BTU air conditioner. Not really suitable for the hot temps! However, by utilizing these 10 tips, we were able to stay relatively comfortable inside the rig. Both us and our refrigerator managed to stay cool. Even on the hottest day of the heatwave (104.5F) the interior temp only reached a max of 80F. More important than that, our ice cream and ice cubes didn’t melt. 🙂
Tips for RVing in Extremely Hot Temps Video
1) Shade Windows and Fridge Vents
A big source of heat build-up in the RV is sunshine pouring in through the windows. We have dual pane windows, which help a little bit but not enough. Blinds and bubble foil still let the heat in. Dark or reflective tinting works better, but then you have to live with it in the cooler months when you’d appreciate more light in the rig. I have found exterior shades to be a decent solution. The meshed shade material blocks the heat on the outside of the window and still leaves a sort of a view and some light inside the RV.
A second big source of heat in the RV is from the refrigerator. In hot weather, the fridge works harder and produces tons of heat. The fridge has exterior vents and a cooling stack to remove the heat from the rear cavity of the fridge. Heat build-up in this cavity (aka chimney or cooling stack) transfers through thin RV walls and into the rig’s living area. Another problem is the fridge’s efficiency is greatly reduced and has trouble maintaining cool enough temps.
I utilize the RV awning and an extra sunscreen to shade the RV’s lower fridge vent and sidewall. I also have installed temperature-controlled fans on the lower and upper vents. The lower fan sucks cooler air into the back of the fridge and the upper one sucks it out the rooftop vent. The two fans work in tandem to increase the natural chimney effect to keep the fridge piping cool.
2) Air Conditioner Maintenance
The RV air conditioner is vital in extreme temps. So, you have to make sure it is in tip-top shape. Keep a clean filter on the inside and check the ducts for blockages or loose sealant tape. Every so often, I pull the outside covers and clean both the condenser, evaporator coils, and fan blades. Dirt and grime buildup on these can dramatically reduce the cooling efficiency.
3) Clean Roof + Skylight Shade
A substantial portion of heat enters through the RV roof. Most are poorly insulated. To help with this, make sure it is as clean as possible. A dirty roof will be darker, so gets hotter. Recently I recoated my roof with a paint-on coating designed to reflect UV and heat. It made the roof sparkling bright white and much cooler to the touch. Just in time for the heatwave.
While up on the roof I attached a piece of my window exterior shade material to the shower skylight, another major source of heat intrusion. The shade blocks the heat before it can enter the shower stall.
4) Electric Fans to Move Air
I have several electric fans in the trailer to help out with air circulation and heat removal. I have a quiet, compact adjustable Caframo fan mounted in the living area for personal cooling. Then we have roof vent fans in the kitchen and bathroom, which I utilize to remove heat buildup from the rig and draw in the fresh air in the cooler evening hours.
They become even more important if we are boondocking since they all are 12VDC to run off the batteries and have low power draw. For more off-grid cooling tips see my post “Tips for Keeping the RV Cool Without AC“.
5) Release Trapped Heat
Every evening it’s important to release trapped heat. I open up the storage bays, cupboards, and closets, letting it all out before bedtime. This makes for a more comfortable night’s sleep and helps start the next hot day with a buffer of cooler air in them.
6) Reflextix Bubble Foil
Speaking of cupboards. For most of them, I have lined the exterior facing walls with Reflectix foil bubble insulation. It works in the summer to keep cool in and repel heat back out. Just make sure to check once in a while behind them for moisture. In some environments, moisture buildup could lead to mold growth. It hasn’t been an issue for me as I don’t spend much time in moist climates and if I do run a dehumidifier to keep the moisture at bay.
7) Run Water Heater on Propane
This is mainly for 30 amp RVs, but I think it’s helpful to switch the water heater over from electric to LP gas mode in hot weather. This will reduce the RV’s overall power draw, helping keep the power cord, plug, and breakers from overheating or blowing.
8) Start Cooling Early
If you think it will be a scorcher, start cooling the RV down early. Set the AC lower and cool more than you need early. Creating a buffer of cooler air will extend the time it takes for the day’s heat to overwhelm things.
9) Roof Vent Cushions
Block hot air from entering via the uninsulated roof vent cavities by inserting insulated vent cushions. The cushions are available in fuzzy white wool material or foil-wrapped. As soon as the inside air is the same temp as the outside air, I shove them in and take them out when the outside air is cooler.
10) Turn Off Heat Creators
Finally, look around the RV and unplug or turn off any unnecessary electronic devices like TVs, computers, chargers, etc. They are like tiny little heaters and combined can add up to quite a few watts of heating power.
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