One of the most common questions we receive during the summer is:
“Why isn’t the RV staying as cool as my house would?”
If it’s your first time renting an RV, this is a completely normal question—and the answer is simple:
An RV air conditioner works very differently than the central air conditioning system in your home.
A house is built with thick insulation, attic ventilation, and a large HVAC system designed to cool thousands of square feet. An RV, on the other hand, is built to be lightweight and mobile. It has thinner walls, more windows, and a roof that’s sitting directly in the summer sun. That means your RV is constantly absorbing heat throughout the day.
Even though your RV’s air conditioner is working hard, it has to continuously remove that heat as fast as it’s entering the coach.
How Does an RV Air Conditioner Work?
Instead of trying to cool the outside temperature, an RV air conditioner continuously recirculates the air that’s already inside the RV.
Warm interior air is pulled into the air conditioner, cooled as it passes over the evaporator coil, and then blown back into the living area through the ceiling vents. This process repeats over and over until the thermostat reaches the desired temperature.
A properly functioning RV air conditioner will typically cool the air passing through the unit by 16–22°F, with about 18–20°F being considered ideal. This is known as the temperature split and is one of the best ways technicians determine that an air conditioner is operating correctly.
The “20-Degree Rule” Explained
One of the biggest misconceptions about RV air conditioners is that they can only make the RV 20 degrees cooler than the outside temperature.
Fortunately, that’s not true.
The “20-degree rule” refers to the difference between the air entering the air conditioner and the cold air coming out of the vents—not the difference between the outdoor temperature and the inside of the RV.
For example:
- Air entering the A/C: 80°F
- Air leaving the vent: 60°F
That’s a 20-degree temperature difference and exactly what you’d expect from a properly operating RV air conditioner.
What Temperature Should You Expect Inside?
Every camping situation is different. The outside temperature, humidity, direct sunlight, number of air conditioners, and size of the RV all affect how cool the interior will stay.
As a general guideline, here’s what many RV owners experience during the summer:
| Outside Temperature | Typical Interior Temperature |
|---|---|
| 80°F | 68–72°F |
| 90°F | 72–78°F |
| 95°F | 75–82°F |
| 100°F | 80–85°F |
If you’re camping in full sun during a 100°F afternoon, it’s completely normal for the air conditioner to run continuously. In fact, that’s exactly what it’s designed to do.
Tips to Keep Your RV Cooler
A few simple steps can make a big difference in keeping your RV comfortable.
- Start the A/C Early: Turn the air conditioner on in the morning before the RV heats up. It’s much easier to maintain a cool temperature than it is to cool down an RV that’s already been sitting in the sun for hours.
- Close the Blinds: Sunlight coming through the windows creates a greenhouse effect. Keeping your shades closed during the hottest part of the day helps reduce heat buildup.
- Use Your Awning: If weather permits, extending your awning shades the side of the RV and helps reduce the amount of heat entering through the windows.
- Keep Doors Closed: Every time the door opens, cool air escapes while hot, humid air rushes inside. Limiting trips in and out helps your A/C keep up.
- Cook Outside: Using the stove or oven adds extra heat to the RV. Grilling outside or preparing cold meals can help keep the interior cooler.
- Park in the Shade: When possible, choose a shaded campsite. Even a few hours of afternoon shade can noticeably improve your RV’s comfort.
Is My RV Air Conditioner Working Properly?
Before every rental, our team thoroughly inspects each RV—including the air conditioning system—to ensure it’s operating as designed.
If your air conditioner is blowing cold air and running consistently, chances are it’s doing exactly what it should. During periods of extreme heat, even a perfectly functioning RV A/C may not keep the interior as cool as your home’s central air.
Enjoy the Journey
Summer camping is one of the best ways to make memories with family and friends. Understanding how your RV’s air conditioning system works helps set realistic expectations and ensures you can enjoy your trip without unnecessary worry.
At Fireside RV Rental, we want every guest to have an amazing experience. If you ever have questions before or during your trip, our team is here to help.
We hope this gives you a better understanding of how RV air conditioners work—and helps you stay comfortable wherever the road takes you.
Happy camping!
