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How to Clean a HEPA Filter: 6 Cleaning and Maintenance Tips

Clean filters = cleaner air.

HEPA filters work hard to remove over 99 percent of allergens. But if you haven’t cleaned your HEPA filter in a while, it won’t clean the air as effectively.

Whether your HEPA filter is in your vacuum cleaner, air purifier, or respiratory mask, you may need to clean it often. But this depends on whether it’s disposable, washable, or permanent.

Before you get into our methods for how to clean a HEPA filter, make sure to check the user manual for specific instructions to avoid damage.

Key Takeaways

  • Permanent HEPA filters should be vacuumed, not washed, to avoid damage.
  • Washable HEPA filters can be rinsed with water, and some can be cleaned with soapy water or in a dishwasher.
  • Clean permanent and washable filters every three to six months, or more frequently if needed.
  • Replace HEPA filters when they are discolored or worn, and maintain them regularly to prolong their life.

How to Clean a Permanent HEPA Filter

If you have a permanent filter, it might surprise you that you shouldn’t wash it. We’ll get into our specific instructions below.

  • Time: 30 minutes
  • Difficulty: Easy/Intermediate

What You’ll Need

  • Old sheets to cover floor
  • Water
  • Soft-bristled brush
  • Sponge
  • Vacuum cleaner with nozzle or soft brush attachment
  • Towel

1. Remove Filters

Permanent HEPA filters are generally found in air purifiers. These should not be washed as water can damage the filter (1).

Before removing the filters, consider covering the floor in plastic or old sheets. You might even take the appliance outside. This is because HEPA and pre-filters can hold a significant amount of dust and dirt.

Start by turning off the appliance and unplugging it to ensure it’s safe to remove the filter. If you’re unsure how to remove it, refer to the manual for directions. Most air purifiers have a back cover that you can open to access the filters easily.

2. Clean the Pre-Filters

With permanent HEPA filters, there’s usually a pre-filter and activated carbon filter. Remove and clean these, too.

You can rinse the pre-filter with water — do this under the faucet and continue until the water runs clear. You should clean fine wire filters gently with a soft-bristled brush. You can also use a damp sponge to wipe both sides of the filter.

You should vacuum the activated carbon filter gently to remove dust and dirt. Clean both sides with the vacuum using horizontal motions. If the carbon filter has absorbed a significant amount of odors, you can leave it in direct sunlight for an hour or two.

If you wash foam or carbon pre-filters, towel dry them and allow 24 hours to dry entirely.

Take Note

Always refer to the manual before washing any filters.

3. Vacuum the HEPA Filter

Once the pre-filters are cleaned and drying, turn your attention to the permanent HEPA filter. For this, you can use any vacuum — we prefer a handheld for ease of use. Use a nozzle or soft brush attachment when cleaning the filter. This will prevent damage caused by the vacuum.

Vacuum using horizontal motions and keep going until all dirt, debris — and potential dust bunnies — are gone. Be gentle as you vacuum; don’t push the attachment into the filter. Instead, set the vacuum to a stronger suction so it will remove deeply embedded dirt.

4. Reassemble

Reassemble by placing the HEPA filter in first, followed by the activated charcoal, and lastly, the pre-filter.

Quick Tip

If your pre-filters are washed and need to dry for an extended period, cover the HEPA filter in plastic so it will stay clean while the others dry.

How to Clean a Washable HEPA Filter

If you have a washable HEPA filter, you can do just that — wash it.

  • Time: 30 minutes
  • Difficulty: Easy

What You’ll Need

  • User manual
  • Old sheets to cover floor
  • Soft-bristled brush
  • Garden hose or shower head (optional)
  • Dish soap (optional)

1. Check the Manual

Before attempting to wash a HEPA filter, read the manual carefully.

You can clean some with soapy water or only rinsing. Some washable HEPA filters are even dishwasher safe.

If you can’t find the manual or you don’t have one, you can search online. Find the manufacturer’s site and type in the model number. You might be able to find a downloadable copy too.

Keep In Mind

Avoid using information from any source other than the unit manufacturer. Washing a non-washable filter can void a warranty in some cases.

2. Remove Filters

Before opening the appliance, you might want to cover the floor or take it outside. If the filters are large, they can hold a significant amount of dirt and dust that they might release into the air or fall to the ground.

Always start by turning the appliance off and unplugging it. This will prevent any potential electrical shocks.

Then, locate the filters and remove them. If you’re unsure how to get to the filters, refer to the manual for guidance.

3. Clean Pre-Filters

If there are any pre-filters, start by cleaning them. These can either be rinsed with water or gently cleaned with a brush. Refer to the manual to ensure they’re washable before attempting to do so. Most appliances with washable HEPA filters will also have washable pre-filters.

If they’re washable, rinse under the sink until the water runs clear. Pre-filters usually hold all of the larger dust bunnies and dirt, so if it’s filthy, start by brushing debris off. This will make it easier to rinse as well.

4. Rinse

After the pre-filters are cleaned and drying, it’s time for the HEPA filter. You can rinse smaller filters under the faucet in the kitchen or bathroom. Larger filters might need to be rinsed outside using a garden hose or a handheld shower head in the shower.

When rinsing, avoid using high pressure as this can damage the filter. Instead, use low to medium flow and wipe your fingers across gently to help loosen dirt.

Some manufacturers recommend soapy water, while others recommend using either cold or lukewarm water. Refer to the manual for specific requirements.

Flat HEPA Filters

These should be washed on both sides to remove all dirt and contaminants. You should only rinse cylindrical filters on the outside — avoid getting the inside of the cylinder wet.

5. Dry

Washable HEPA filters should air dry completely before being reinstalled. After washing the filter, you can give it a quick shake to remove excess water. Set the filter up outside against a wall or chair to get fresh air from all sides.

Keep In Mind

You should never try to speed up the process by using a blow dryer or clothes dryer. This will damage the filter and might even void a warranty. Always allow the washable HEPA filter to air dry.

6. Reassemble

When the filters are completely dry, it’s time to reinstall them. Start with the HEPA filter and follow with pre-filters. Refer to the manual if you’re unsure.

How to Maintain a HEPA Filter

Maintaining your HEPA filter will ensure it’s working at an optimal level at all times. Regularly cleaning a reusable filter will also help to prolong the life of the filter and appliance. Here are a few tips to help you maintain your HEPA filter:

1. Clean When Recommended

Air purifiers with washable or permanent filters are usually required to be cleaned every three to six months. Following this recommendation will help to keep your filter clean and running smoothly.

2. Clean When Needed

Although you should follow the above tip, you might also want to set your own timer. Consider how often you run your air purifier or use your HEPA-filtered vacuum. The more frequently you use the appliance, the dirtier it will get, thus requiring more cleaning.

If you use your air purifier in a dusty room, it will become dirtier than in a relatively clean environment. We highly recommend you check the filter regularly to see how dirty it is and clean it if needed.

3. It’s Safe to Clean the Filter More Often

Don’t be afraid to clean the HEPA filter more often than the manufacturer recommends. If it’s dirty, clean it — it’s perfectly safe if you use the correct methods. Also, keeping your HEPA filter clean will help the appliance to work more efficiently.

4. Set a Reminder

Many air purifiers are equipped with an electronic reminder to clean the filter. Some are more high-tech than others — equipped with sensors that detect how dirty the filter is. Others might be as simple as a wheel you can set to the month when cleaning is needed.

Although a reminder comes in handy, you shouldn’t rely entirely on it. As mentioned above, frequent appliance use will require more frequent cleaning.

5. Don’t Clean If Not Necessary

If you don’t use the appliance as often, you won’t need to clean it as often. Once every three months might even be too often.

Check the filter when cleaning is due; if it isn’t dirty, avoid the trouble. You can, however, give it a quick go with the vacuum if you feel it’s necessary.

6. Replace If Needed

Even permanent doesn’t mean forever-lasting. Sooner or later, the HEPA filter will be worn and require replacement. When you notice a decrease in the appliances’ efficiency, and cleaning the filter isn’t helping, it might be time for a change.

Cleaning Prolongs Filter Life

Regularly cleaning the filter will help to prolong its life; it might last for years. Conversely, neglecting your filter for a long time will cause it to deteriorate quickly and wear out.

Most manufacturers recommend that you replace the HEPA filter when it becomes discolored or worn.


How Do I Know If My HEPA Filter is Dirty?

There are several signs that your HEPA filter is dirty, including an increase in allergies, clothes discoloring when placed near vents, and more expensive electricity bills. You might also hear your HVAC system making weird noises or running more frequently.

What Happens If You Don’t Wash a Hepa Filter?

If you don’t wash a HEPA filter, it becomes clogged and eventually stops working. Allergens escape and contaminate your indoor air, affecting your family’s health.

Can a Dirty Air Filter Make You Sick?

A dirty air filter can make you sick because it fails to trap pollutants. When that happens, indoor air quality drops, and people suffer with health side effects.

When Should I Change My HEPA Air Filter?

You should change your HEPA air filter at least once every year. If you have permanent filters, wash them once every three months. The timescale also depends on how much use the filter gets, especially if you have pets and kids.

How Can I Make My Air Purifier Filter Last Longer?

You can make your air purifier filter last longer if you regularly dust, vacuum, and restrict the amount of dust and allergens that enter your home. The fewer pollutants it traps, the longer it will last.

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About the Author

Matthew Sullivan

Matthew Sullivan is a technical writer with over 15 years of hands-on experience in the realm of HVAC, humidity, air purification, and mold prevention. With a background rooted in mechanical engineering, Matthew seamlessly blends the intricate world of technicalities with the everyday challenges that homeowners and businesses face. His vast expertise has led him to collaborate with leading HVAC manufacturers, consult on cutting-edge air purification systems, and become a sought-after voice on mold mitigation.