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Reading Time: 4 minutesLast Updated on October 28, 2026 by Paul Clayton
Part of our guide: RV Air Conditioning Troubleshooting Guide
To clean an RV air conditioner filter, turn the AC off, remove the return-air grille on the ceiling assembly, pull out the foam or mesh filter, wash it in warm water with a little mild dish soap, rinse it from the clean side out, and let it dry completely before putting it back. Do it every two to four weeks when the AC runs daily, and more often in dusty campgrounds or if you have pets. A clean filter is the single easiest way to keep an RV AC cooling well and to prevent frozen coils.
Table of Contents
Key Takeaways
| Topic | Key takeaway |
|---|---|
| How often | Check monthly in heavy use; clean every few weeks |
| How to clean | Remove the filter, wash with mild soap and water, dry fully |
| Replace when | Torn, warped or clogged |
| Why it matters | Better airflow, cooling and air quality |
| Bonus | Also check coils and vents |
Where the RV AC Filter Is
Most rooftop RV air conditioners have their filters in the ceiling assembly inside the coach, the plastic shroud with vents directly under the rooftop unit. You don’t need to climb on the roof.
- Non-ducted units: the filter sits behind the return-air grille in the center of the ceiling assembly. Many grilles snap off or slide out; others have a few screws.
- Ducted units: the filter is still behind the central return grille, while cool air goes out through ceiling vents around the coach.
- Some designs use two smaller filter pads that slide out from slots on either side of the ceiling unit.
- Basement or ducted heat pump systems may use a standard pleated filter in a return vent near the floor. Check your owner’s manual if you can’t find it overhead.
How to Clean an RV Air Conditioner Filter, Step by Step
1. Turn the AC off
Switch the thermostat off so the fan isn’t pulling air while the filter is out. Running without a filter lets dust coat the evaporator coil.
2. Remove the grille and filter
Pop off or unscrew the return-air grille and set the screws somewhere safe. Pull the filter out gently; old foam can be brittle.
3. Knock off loose dust
Tap the filter outside or go over it with a vacuum brush attachment. This removes most of the debris before it turns to mud in the sink.
4. Wash it
Soak it in warm water with a few drops of mild dish soap, then squeeze it gently. Don’t wring or twist foam filters. Rinse with clean water, running it from the clean (room) side toward the dirty (coil) side to push dirt out the way it came in. A detachable RV shower head or a garden hose on a gentle setting works well.
5. Dry it completely
Press out the water with a towel and let it air-dry in the shade. Putting a damp filter back can grow mildew and blow musty air through the coach. Skip the hair dryer on high heat, which can warp foam.
6. Clean the grille and reinstall
Wipe the grille with a damp cloth, slide the filter back in the right direction, and reattach the grille. Turn the AC on and check that air flows strongly from the vents.
Tip: keep a spare filter on hand so you can swap in a clean one right away and wash the dirty one at your leisure.
How Often to Clean or Replace It
| Situation | Clean the filter |
|---|---|
| Occasional weekend use | Monthly during the season |
| AC running daily | Every 2 to 4 weeks |
| Dusty, desert or gravel campgrounds | Every 1 to 2 weeks |
| Pets, smoking or heavy cooking | Every 1 to 2 weeks |
| Start of each season | Always, plus a quick look at the rooftop coils |
Replace the filter when the foam tears, crumbles, gets thin in spots or stays discolored after washing. Buy the replacement made for your AC model (Dometic, Coleman-Mach and Furrion all use different sizes), or cut generic RV filter foam to fit the old one.
Signs Your Filter Needs Attention
- Weak airflow from the vents even on high fan
- The AC runs constantly but the coach doesn’t cool
- Ice forming on the coils or water dripping from the ceiling unit
- Dusty or musty smell when the AC starts
- The unit cycles on and off more than usual
A clogged filter starves the evaporator coil of airflow, so the coil gets too cold and freezes. It also makes the compressor work harder, which raises how many watts your RV AC draws.
Other Ways to Keep Your RV AC Running Well
- Clean the coils. Once or twice a season, remove the rooftop shroud and gently clean the condenser and evaporator fins with a soft brush or no-rinse coil cleaner. Straighten bent fins with a fin comb.
- Check the shroud and gasket. A cracked shroud or a worn roof gasket can let in debris and water. See our guide to an RV air conditioner that leaks when it rains.
- Help it out on hot days. Park in shade, close blinds on the sunny side, and start the AC early in the day rather than trying to cool a hot coach in mid-afternoon.
- Manage humidity. Damp air feels warmer and loads up the coil. Learn whether you need a dehumidifier when the RV AC is running.
- Consider an upgrade. If your unit is old and loud, a newer quiet RV air conditioner can cool better on less power.
Frequently Asked Questions
Can I use a disinfectant spray on my RV AC filter?
You can lightly mist a dry, clean filter with a household disinfectant spray to reduce odors, but let it dry before reinstalling. Never spray cleaners into the unit while it’s running.
Can I run my RV AC without a filter?
Only for a few minutes. Without a filter, dust and pet hair go straight onto the evaporator coil, which is much harder to clean than the filter.
Can I put an RV AC filter in the washing machine?
It’s not recommended. Agitation can tear foam filters. Hand washing is quick and gentler.
Are RV AC filters universal?
No. Sizes vary by brand and model. Check the model number on the ceiling assembly or in the manual before ordering.
Why does my RV AC smell musty after cleaning the filter?
The filter may have gone back in damp, or mildew may be growing on the coil or in the drain pan. Dry the filter fully and clean the coil if the smell continues.
Final Thoughts
Cleaning your RV air conditioner filter is one of the easiest ways to keep cool and protect your AC. Make it part of your monthly routine during the cooling season.
Resources
- RV air conditioner manufacturers’ owner manuals
