RV Air Conditioners: DIY Maintenance Guide
- Just CAMP Wait
- May 1
- 4 min read
Updated: May 6
Whether you're trekking across the desert, camping lakeside mid-summer, or enjoying the waves at a beach front RV park, your RV air conditioner is a must-function appliance for an enjoyable trip. Let’s face it, many of us are more into glamping than camping. Yet for many RVers, the rooftop AC unit is “out of sight, out of mind”—until it stops working.
How an RV Air Conditioner Works
An RV air conditioner operates using the same basic principles as a residential refrigeration system, but it's packaged in a compact, rooftop-mounted unit designed specifically for RVs. The system uses a closed-loop refrigerant cycle to remove heat from the inside of your RV and release it outside. Here's how it works step by step:
Inside the AC unit, the compressor pressurizes a refrigerant gas, turning it into a high-pressure, high-temperature vapor. This vapor travels through the condenser coils, where a fan blows outdoor air over the coils to dissipate heat and condense the refrigerant into a liquid. That cooled liquid then moves into the evaporator coils inside your RV. As warm indoor air is drawn in by a blower fan and passes over the evaporator, the refrigerant absorbs the heat, cooling the air, which is then circulated back into the living space. The refrigerant, now warmed and evaporated again, returns to the compressor to repeat the cycle.
Because the system uses electricity (120V AC) and draws significant amperage—usually 13 to 16 amps—it must be powered by either shore power, a generator, or a large inverter system. Most units are controlled by a thermostat that cycles the system on and off based on your temperature settings. Effective cooling relies not just on this cycle but also on good airflow, clean filters, and well-maintained components.
Routine Maintenance
1. Clean or Replace the Air Filters (Monthly)
Why: Dirty filters reduce airflow, efficiency, and indoor air quality. If your system is starved for airflow it is likely to overheat and damage the system. Not having a filter can lead to the coils getting clogged with debris which will also restrict airflow.
How to:
Remove the ceiling grille and remove the factory foam filters.
Wash the reusable foam filters with warm soapy water.
Let them dry completely and reinstall.
2. Clean the Evaporator and Condenser Coils (Every 6 Months)
Why: Dust, debris, and grime insulate the coils, reducing heat exchange and overworking the compressor.
How to:
Turn off the air conditioner and the A/C breaker.
Remove the rooftop shroud and interior cover.
Inspect for any signs of leaking refrigerant (wet spots) or physical damage.
Use a coil cleaner to gently clean the coil fins.
Use a fin comb to gently straighten any bent or damaged fins
3. Check and Clear the Drainage Path (Every 6 Months)
Why: AC units remove humidity. If the drain pan or condensate line is clogged, water may leak into the RV from the air conditioning unit.
How to:
Check for debris around the base and pan underneath the shroud
Use a soft brush or pipe cleaner to unclog openings in the pan and sweep out all debris
4. Inspect the Shroud (Every Trip)
Why: The plastic shroud protects the unit from weather and debris. Cracks or broken pieces can allow water in or reduce efficiency leading to damage.
How to:
Look for cracks or UV damage.
Replace the shroud if it’s warped or brittle.
5. Thermostat functionality (Every Trip)
Why: A faulty thermostat can lead to erratic cycling and insufficient or no cooling.
How to:
Raise the temperature and listen for the “knock” from the A/C indicating the compressor has kicked on and the system is blowing out cold air
Cycle the high and low fan settings and check that the fan speed changes
Use a digital thermometer to compare room temp to thermostat setting.
6. Check the Duct Air Temperature (Quarterly)
Why: When an RV air conditioner is running properly, the air coming out of the vents should be about 16–22°F (8–12°C) cooler than the air going into the return (intake) vent. Anything outside of this range can indicate a refrigerant leak, failing components, or poor airflow through the system.
How to:
Measure the Return Air Temperature
Place your thermometer probe just inside the return vent or point your IR thermometer at the intake grill.
Record the temperature of the warm air being pulled in.
Measure the Supply Air Temperature
Place the probe inside the closest air supply vent or use the IR thermometer to read the airflow surface temperature.
Record the temperature of the cool air being blown out.
Calculate the Temperature Split
Return Temp - Supply Temp = Temperature Split (Delta T)
A healthy system should have a Delta T of 16–22°F (8–12°C).
Anything less than 14°F may signal reduced efficiency or a potential problem.
Tools and Products for DIY Maintenance
Product Name with Link | Purpose | Top Features | Rating |
Coil cleaner for evaporator/condenser | Foaming action, no rinse needed, safe on aluminum | ⭐ 4.8/5 | |
Reduces interior noise | Easy install, includes high-efficiency air filter | ⭐ 4.7/5 | |
Soft start for AC units | Run AC on small generators/inverters, tech support | ⭐ 4.8/5 | |
Smart thermostat upgrade | Touchscreen, Wi-Fi, Bluetooth, wide compatibility | ⭐ 4.9/5 | |
Filter replacement/upgrade | Cut-to-fit foam, improved airflow | ⭐ 4.6/5 | |
Diagnose temperature split (Delta T) | Accurate IR readings, fast response | ⭐ 4.7/5 | |
Straightens bent condenser/evaporator fins | Multi-size tool, restores airflow, protects coil fins | ⭐ 4.6/5 |
Click the in-text links to see the products on Amazon
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