How to Find and Replace Your Camper's AC Filter

What a camper AC filter does and why it matters

Your camper's air conditioning system pulls air through a filter before cooling it. That filter traps dust, pollen, pet hair, and debris that would otherwise clog the AC coils and reduce cooling power. A dirty filter makes your AC work harder, cool slower, and use more power — which matters in a camper where your battery or generator has limits.

Unlike a car engine filter, a camper AC filter is usually straightforward to access and replace yourself. Most campers use one of two types: a slide-out panel filter in the return air duct, or a cartridge filter inside the AC unit itself. Knowing which one you have determines where you look and what size replacement to buy.

Key Takeaways

Camper AC filters come in two main types: slide-out panel filters in the air return, or cartridge filters inside the AC unit, and you need to know which one yours is before buying a replacement.
Panel filters are typically 16 by 25 inches or similar standard sizes; cartridge filters vary widely by manufacturer and model, so you should check your owner's manual or the old filter itself for the exact dimensions.
A clogged filter reduces cooling power and increases power draw, which is especially noticeable in a camper running on battery or generator.
Most camper AC filters should be checked every month during cooling season and replaced when they look gray or caked with dust, usually every one to three months depending on use and air quality.

Finding your camper AC filter location

Start by checking your owner's manual — it will show you exactly where the filter is and what size to order. If you do not have the manual, look for the AC unit itself, usually mounted on the roof or in a wall cabinet.

Panel filters are mounted in the return air duct, often behind a removable grille or panel in a cabinet, closet, or bedroom wall. You will see a rectangular frame with pleated material. Cartridge filters sit inside the AC unit itself, so you may need to open an access panel or remove a cover to see it. If you are unsure, take a photo of the area and search for your camper model online — forums and YouTube videos often show the exact location.

Measuring and ordering the right filter

The easiest way to get the right size is to remove the old filter and read the dimensions printed on its frame or edge. Panel filters are usually labeled with three numbers: length by width by depth, such as 16 by 25 by 1 or 20 by 25 by 4. Write down all three numbers exactly.

Cartridge filters are harder to match by eye because they come in many shapes — cylindrical, pleated, or flat — and sizes vary by brand. Check your manual for the part number, or search online for your camper model and "AC filter." RV supply stores like Camping World and online retailers like Amazon carry both common sizes and hard-to-find cartridges. If you cannot find the exact match, call the store with your camper's year, make, and model.

Panel filters are often cheaper and easier to find because they use standard HVAC sizes. Cartridge filters are usually more expensive but last longer and cool more efficiently.

How to replace a panel filter

Turn off the AC unit. Locate the filter frame — it will have a handle or be held in by clips or a sliding track. Slide or pull the old filter straight out. Note which direction the arrow on the frame points; the new filter's arrow must point the same way.

Slide the new filter in, making sure it sits flat and the edges seal against the frame. If it does not slide smoothly, check that you have the right size and that nothing is blocking the opening. Turn the AC back on and listen for any rattling or unusual noise, which would mean the filter is not seated correctly.

How to replace a cartridge filter

Turn off the AC unit and let it cool for a few minutes. Open the access panel or cover to reach the filter. Most cartridge filters are held in place by a center bolt or clip — loosen it and lift the old filter straight up and out.

Before installing the new one, look inside the housing for loose debris or dust buildup. Wipe it out with a dry cloth or vacuum it gently. Slide the new filter down into the housing, making sure the rubber gasket or seal sits evenly all the way around. Tighten the center bolt or clip — snug but not so tight that you crack the plastic frame. Close the access panel and turn the AC back on.

When to replace your camper AC filter

Check your filter once a month during the cooling season. If it looks gray or caked with dust, it is time to replace it. In dusty climates or if you use the AC constantly, you may need a new filter every month or two. In cleaner air or lighter use, one filter may last three months or longer.

Some campers run their AC year-round in warm climates, so check the filter every month regardless of season. If you store your camper for winter, replace the filter before you close it up, so you start the next season with a clean one.

Choosing between standard and high-efficiency filters

Standard panel filters (usually rated MERV 8 or MERV 11) trap most dust and pollen and cost less. High-efficiency filters (MERV 13 or higher) trap smaller particles and allergens but restrict airflow more, which can strain your AC compressor if your unit is not designed for them.

Check your owner's manual to see what MERV rating your AC unit is rated for. If it does not specify, stick with MERV 11 or lower. Cartridge filters often come in only one efficiency level per model, so you do not have to choose.

If anyone in your camper has allergies or asthma, a higher-efficiency filter may help, but only if your AC unit can handle it without overworking. Test it for a week and listen for the compressor running constantly or the air output dropping noticeably.

Frequently Asked Questions

Can I clean and reuse my camper AC filter instead of replacing it?

Panel filters can sometimes be vacuumed gently to extend their life by a few weeks, but they cannot be washed or fully cleaned. Once they look gray or caked, replacement is cheaper than running a strained AC. Cartridge filters should never be washed; water damages the pleats and seals.

What happens if I run my camper AC with a clogged filter?

A clogged filter reduces airflow, so the AC runs longer to cool the same space and draws more power from your battery or generator. Over time, restricted airflow can damage the compressor. Replacing the filter is much cheaper than repairing or replacing the AC unit.

Do I need a special filter for a camper, or can I use a standard HVAC filter?

Standard HVAC filters in common sizes (like 16 by 25) work fine in camper AC systems. The main difference is that camper AC units are smaller and more sensitive to airflow restriction, so avoid very high MERV ratings unless your manual says it is safe.

Where can I buy camper AC filters?

Camping World, Amazon, RV supply websites, and some Walmart locations carry common sizes. For unusual cartridge filters, call an RV service center or the AC manufacturer directly with your camper model and year.

How much does a camper AC filter cost?

Panel filters usually cost between $15 and $40 depending on size and efficiency. Cartridge filters range from $30 to $100 or more for specialty models. Prices vary by retailer and availability in your region.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.