How to Clean Air Conditioner Filters [Quick + Deep Clean]

Written by: Paul Cathro

Updated on: December 27, 2022

In this guide, we explain how to easily clean your AC filters to keep your air cooling system running efficiently.

man removing an AC filter

The primary role of an air conditioner is obviously to cool down our homes but an often overlooked role they have is to prevent dust and other unwanted particles from entering.

Depending on where you live (cities and polluted areas are the worst), the filter in an air conditioner can become blocked quite easily.

If you’ve noticed a drop in the performance of your AC unit, or if there’s a strange smell whenever you turn it on, it’s highly likely that the air filter needs a clean.

In fact, it's actually good practice to clean AC filters as often as every month to keep your AC unit running at its most efficient best.

If you’re wondering how to clean air conditioner filters (mini-split, window AC, portable AC, or any type for that matter) then you can follow our simple steps below.

The Easiest Way to Clean Your AC Filter

Tools Required

The tools you require to remove the air filter will vary depending on your model of air conditioner but most people with a modern AC won't need any. However, you might need a ladder to reach your AC unit.

Here's what you'll need:

  • Ladder (depending on where your AC unit is)
  • Screwdriver (shouldn't be needed in most cases)
  • Soft brush or cloth
  • Vacuum (handheld or traditional vacuum with small nozzle attachment)
  • Shower (or hose with spray attachment)
  • Hair dryer

Step 1  -  Turn Your AC Off

It's usually a pretty straightforward task to remove the filter but you'll want to turn your air conditioner off before you do so. 

The reason for this is that while the air filter is unattached, the AC unit (if still turned on) will blow unfiltered air throughout your home.

Step 2  - Remove the Filter

This is usually a straightforward task that just takes a few moments but if you have an older air conditioner the process might be a little trickier.

Personally, the hardest time I have accessing my air conditioner filter is locating my step ladder to get me up high enough.

Remember, no matter how tempting it is to save time and balance atop a pile of books, the extra few minutes it takes to go out to the garage and get your ladder is always worth taking!

In the case of most split AC systems (that have the noisy compressor unit outside and the wall mounted blower unit inside), the air filter is positioned on the front of the AC unit, behind the grille or front casing.

You will need to remove the front casing to access the filter.

An AC filter being removed

Once you are in position and have a steady base to support yourself (you won't have this problem with a portable AC, or window mount), all you need to do is unclip or push up the front casing (or grille) on the front of your AC.

The casing can sometimes be a bit stiff, but remember it's a part of the unit and should not be removed, just opened.

In some cases, you might need a screwdriver to access the air filter. I've never had to do this but I've seen older air conditioners that have the grille screwed in place.

The air filters should then slide out pretty easily.

If you're not sure of the location of your air conditioner filter or if you're not sure how to access it, then consult the instructions. If they're not available, an internet search for the make and model will usually yield a digital copy.

The images below show the air filters being removed on a mini-split AC and a portable AC.

Cleaning Air Conditioner filters

An air filter being removed on a mini-split AC

Cleaning a portable air conditioner

A grille being removed on a portable air conditioner

Step 3 - Clean the Filter

A quick AC filter clean involves little more than brushing off the grey dust that is collected.

The picture below shows what you can expect.

Dirty air conditioner filters

Typical dusty air conditioner filters

This grey dust material usually comes off with little fuss. You're best using a soft brush or a cloth.

However, once in a while it's best to give them a deeper clean. This is especially important if your AC has not been used for a long time.

Our AC is unused for about 5 months of the year so I give the filters a more thorough cleaning before the weather starts heating up at the end of spring. This is to make sure there has been no build up of mold during the humid winter.

Mold can be harmful to health, and if your AC filters are moldy then you're circulating harmful particles throughout your home.

It's good practice to periodically run your AC for short times throughout these 'down times' to prevent mold from finding a home in your air conditioner.

To give your air conditioner filters a deeper clean, you can first use a vacuum cleaner to remove the dust and large particles that have been collected. A small handheld vacuum is best for this but you can use a regular vacuum that has a small attachment for tight spaces.

Next, use a shower-head or hose attachment with a spray setting. Give the filter a good rinse, getting rid of the tiny dust particles that you may have missed with the vacuum. If you're using a shower to do this you'll probably need to use the highest pressure setting.

Cleaning an AC filter with water pressure

Cleaning an AC filter with water pressure

The most effective way to do this is to spray the water from the opposite side from where the dust has been collected. We want to eject the dust from the filter and not force it deeper into the filter. To clarify, the water should be sprayed like it would come from inside the AC unit and out through the filter.

It's really important to allow the filters to dry properly before putting them back into your AC unit. You can allow them to dry naturally outside in the breeze or you can use something like a hair dryer to expedite the process. It's important to use a hair dryer on a low heat setting though as filters are very fine materials that easily set on fire.

Conversely, don't allow the filters to stay wet for too long either. A cold, wet environment is one in which mold thrives.

Step 4 - Putting it Back Together

Putting things back together shouldn't be a problem. The filters should slide back in quite happily, just check that they are the right way up.

If you encounter any resistance putting the casing back down then the filters are probably not in position correctly.


Reasons to Clean Your AC Filter

Cleaning your AC filters is not only good for your respiratory health, but it also prolongs the lifespan of your AC unit, saving you time and money on repairs and replacements.

A clogged filter is terrible news for your air conditioner because it increases its load of work.

It can no longer easily fill your room with cold air, so it needs to work extra hard to ensure the thermostat temperature is met. This has three negative effects, each costly in their own way.

  • Your air conditioner will become much less energy efficient
  • Your energy bills will go up
  • The lifespan of your AC unit will decrease

On occasions, the airflow of an air conditioner can restricted to such an extent that the AC coils actually freeze.

How Often Should I Clean My AC Filters?

If you use your AC on a daily basis then you should give your air filters a clean every 4-6 weeks. 

For less frequent users, every 10-12 weeks is acceptable. 

If your AC heats as well as cools then this cleaning schedule will need to be maintained year round.

AC Filter Cleaning FAQs

Still have questions? Here are some answers to the problems we get asked about the most.

Does cleaning an AC filter make it colder?

Yes, it's possible you'll notice that your AC runs colder. It really depends how dirty and badly blocked the filters are. 

If they are really dirty and haven't been cleaned in a long time then there's a good chance that you'll notice a big difference in the cooling power of your air conditioner. But, if you're performing regular maintenance then it's unlikely that you'll notice a difference.

Can I run my AC without a filter?

This is not something I advise no. You'll get away with it for a short period but you risk long-term damage to your air conditioner.

The obvious risk is unfiltered air entering your home but there are a couple of expensive issues that can arise if you run your AC without a filter for extended periods.

The air filter prevents unwanted articles entering your home but it also stops them from entering the air conditioner. If unfiltered air is allowed into the AC unit then dirt and dust can build up inside the condensor unit and in the ductwork.

A build-up of dust and dirt in the condensor unit can affect the efficiency while build-up in the ductwork can absorb moisture that can lead to the growth of mold.

Can I clean AC filters myself?

Yes, it's not a difficult task. By doing it regularly you'll ensure it's a really quick job taking just a few minutes.

About the Author Paul Cathro

Paul is an ex-HVAC engineer with 5 years 'in the trade'.

He acquired in 2022 and aims to make it the internet's most comprehensive HVAC resource for small homes in the next few years.

You can learn more about Paul's story here.

Browse his published work on the website here.

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