youtubeCurrently in our area and beyond we are experiencing a heat wave that is shattering temperature records. If you are fortunate enough to be out camping, hopefully your coach has air conditioning. One of the joys of RVs is that most of them have at least one air conditioner. It is days like these that we really need these units to function properly. While our little corner of the world is a true paradise, we only get really hot days for a few weeks (or months if we’re lucky) of the year. My wife grew up in the Okanagan, which is usually the hottest place in Canada in the summer months. Therefore, she has a high heat tolerance, so she prefers to simply open the RV windows most of the time. Yesterday she turned on the air conditioner.

The RV air conditioner is an appliance that is not frequently used by everybody. But as with other RV systems, it is one that really needs to work properly when needed. Fortunately, it doesn’t require much maintenance to keep it running smoothly. Regular maintenance is important in order to avoid expensive surprises, but before we get into what you should do to keep your AC running properly, I would like to explain what an air conditioner can’t do.

It is generally understood that a 13,500BTU rooftop air conditioner in a recreational vehicle can’t cool the inside air more than 20 degrees below the outside air temperature. Generally, the main factors contributing to air conditioner performance are outside humidity and temperature, as well as condition of the AC unit. Putting this in perspective, if it is 90 degrees outside, you MAY achieve 70 degrees inside your coach, but you are not likely to get much lower than that. Having multiple air conditioning units will serve mainly to keep a larger area cool rather than provide more cooling. During the last weekend of June, it was close to 100 degrees outside, so one can expect an AC unit in good condition (and properly maintained) can cool to roughly 80 degrees. As mentioned, the 20 degree delta should be used as a guideline only.

In terms of maintenance, there are really only two things you need to do with a rooftop AC. First, be sure to regularly clean the intake filters. These are the foam filters located behind the ceiling plenum louvres. If you have ducted AC, the filters will be located behind each roof intake duct. Ducted AC units have both exhaust and intake ceiling louvres, and the filters will be located only on the intake louvres. There will also be a filter located behind the main ceiling plenum louvre, as with non-ducted units. Simply snap off the louvre cover to access the filter. For the duct louvres, just pop the round louvre out of the surrounding plenum by giving a firm pull.

The foam filters are reusable and can be washed and/or vacuumed clean. In the case of washing, simply wash the filters in water with dish soap, then rinse them clean and wring them dry. Make sure they are completely dry before running the air conditioner. You can purchase the foam material online or from some RV and home improvement stores. I keep a spare sheet or two so I can cut a new filter if one becomes damaged.

The second maintenance item that should be performed on a rooftop AC is to inspect the condenser fins on the roof. If it is not safe to do so, or if you are not comfortable mounting the roof of your RV, do not do so, seek professional assistance. The same applies if your RV roof cannot support your weight. This can be hard to determine, but if your coach has a ladder, it is safe to assume your roof can support your weight. If it does not have a ladder, consult your owner’s manual or manufacturer for assistance. Exercise extreme caution when on the roof and stay away from the edges. As mentioned, do NOT attempt to climb onto the roof if it is unsafe, such as when icy or wet.

Once on the roof, inspect the exposed condenser fins for debris or damage. If the fins have more than a few square inches of bent fins, I would recommend using an air conditioner fin comb to straighten them. You can also clean the condenser with a garden hose, but do not use compressed air or a pressure washer.

Performing these simple tasks annually should keep your air conditioner running efficiently. Other summer camping tips can be found here.

Questions? Comments? Please add your thoughts below.

Steve Froese
Author: Steve FroeseEmail: This email address is being protected from spambots. You need JavaScript enabled to view it.
Steve Froese is a Licensed Professional Engineer in British Columbia, as well as an Interprovincial Red Seal RV Technician, which is equivalent to a Master Certified RV Technician in the USA. Steve was a personal friend and colleague of the late Gary Bunzer (“the RV Doctor”), and works closely with FMCA as the monthly “Tech Talk” columnist, as well as being a member of the Technical Advisory and Education Committees. Steve and his family are lifelong and avid RVers, mostly in the Pacific Northwest.

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