RV A/C Overview: How Cooling Units Work

There’s a fairly common misunderstanding about the capabilities of RV A/C units in the sense that many RVers expect them to cool a hot vehicle in no time flat. After returning from a hike on a 95-degree day, my RV should be cool and comfortable as soon as I kick on the A/C, right?

That would be pretty great, but it’s an unrealistic fantasy. The fact is, that’s not how air conditioning works. In this lesson, we dispel the myth of the magical RV A/C unit, teach you how these appliances actually operate, and give you a few important tips for making your unit run a little more efficiently.

What Goes on in Your RV A/C Unit?

To help you better understand how your RV A/C unit works, RV maintenance expert Dave Solberg and RVIA Master Technician Steve Albright walk you through a quick overview of the types and functionality of the air conditioning units found on most vehicles. Whether you opt for a roof-mounted, duct-driven unit or a newer model that sits underneath the carriage of your motorhome, it operates in generally the same the way.

There are four major components that make up an RV A/C unit, each of which Steve inspects on a demonstration model. The evaporator is the most essential part in the cooling process, responsible for pulling warm air out of the vehicle and slowly recirculating it to drop the temperature by small increments.

Making Your Unit More Efficient

Addressing the belief that A/C units should be able to instantly cool a space, Dave and Steve talk about the limited capabilities of all units, regardless of quality, cost, and type. There’s simply no way to make the temperature plummet. So what can you do to help your RV A/C unit run more efficiently and expedite the cooling process? First and foremost, get your vehicle under shade—stat! Limiting sun exposure will keep your baseline temperature lower, and you’ll get comfortable much quicker! Keep your RV in the shade as much as possible throughout the day.

5 Responses to “RV A/C Overview: How Cooling Units Work”

1. William dusenbury September 2nd, 2021

   My 1999 fleetwood a.c.,s arooftop first a.c.,has 2 wires 1 black,1 white. Coming out opposite wall all runs however no cool at all?

   Reply

   • Customer Service September 3rd, 2021

     Hello William,

     Great question! The ‘Ask an Expert’ section is currently for members of our online community. By becoming a member, you will have access to our expert’s knowledge. With your membership you will also receive discounts on products and hours of Premium video content.

     If you are interested in becoming a member, please click on the special offer below:

     https://go.rvrepairclub.com/a19774/

     Thanks!

     Sarah
     RV Repair Club Video Membership

     Reply

2. Judith May 26th, 2020

   So its OK to have roof air vents open when running the AC? I understand the sense of having doors and windows closed, as well as that hot air rises so it would make sense that the hot air in the RV would travel out of the roof vents. But how long do you leave them open? Just a short time?

   Reply

   • Customer Service May 29th, 2020

     Hi Judith,

     Here is the experts reply:

     The only time you would want them open is initially when first starting to try to cool down to help get the bulk of the heat out, about 5 minutes or so. It is better for everything to be buttoned up when running the AC as it recirculates the air. Takes in the hot air, passes through the evaporator which removes heat and moisture and then puts it back into the room. If you leave vents open you are just letting hot air and moisture back in which makes the system less efficient. You don’t want anything to be open. You can open the vent at the beginning for a short period to help push out some heat but really it is best to leave everything shut for the system to work best.

     Sincerely,

     Dan
     RV Repair Club Technical Expert

     Reply

3. Jeanie December 9th, 2018

   The roof air conditioner on our ’72 Winnebago Scrambler has slowly stopped cooling. Can anyone recommend someone in the Minneapolis area that might be able to check it for leaks and then put new coolant in it? We last put coolant in it back in the mid-90’s, which got it working fine again, but now the original type freon is not commonly available, plus the air conditioner might have developed leaks since then. It worked somewhat two years ago. We haven’t used it very often, as we don’t travel much in the hottest part of summer, plus have a ceiling exhaust fan that works wonderfully, but there are times the air conditioner comes in handy.

   Reply