How to Clean a HEPA Filter

Dirty filters can’t clean air.

HEPA filters are used in many appliances such as vacuum cleaners, air purifiers, and respiratory masks. There are many different types of HEPA filters, the most effective being a True HEPA.

These filters are manufactured as disposable, washable, or permanent.

Reusable HEPA filters are easy to maintain, but you must keep in mind that a permanent filter isn’t washable. In fact, if you wash a permanent HEPA filter, it will be ruined. So before you attempt to clean your HEPA filter, check the manual to ensure you won’t damage it.

How to Clean a Permanent HEPA Filter

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. These may then enter the air or fall to the ground.

Start by turning off the appliance and unplugging it to ensure it’s safe to remove. 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

Permanent HEPA filters rarely come alone. There’s usually a pre-filter and an activated carbon filter. These should be removed and cleaned as well.

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

The activated carbon filter should be vacuumed 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 type of 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

Once the permanent HEPA filter and pre-filters are clean, it’s time to put everything back. Reassemble by placing the HEPA filter in first, followed by the activated charcoal and lastly the pre-filter. Again, if you’re unsure, refer to the manual for specific instructions.

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

1. Check the Manual

Washable HEPA filters are used in air purifiers as well as vacuums. Before attempting to wash a HEPA filter, read the manual carefully.

Make sure it’s washable, some will also state how it should be washed, for example, with soapy water or only rinsing. Some washable HEPA filters are even dishwasher safe.

If you can’t find the manual or you simply 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 any information from any source other than the manufacturer of the unit. Washing a non-washable filter can void a warranty in some cases.

2. Remove Filters

Before opening up 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 might be released 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 very dirty, 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. Smaller filters can be rinsed under the faucet in the kitchen or bathroom. Larger filters might need to be rinsed outside using a garden hose, or in the shower using a handheld shower head.

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. Cylindrical filters should only be rinsed 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 so it can 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 all of 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 the above tip should be followed, you might want to set your own timer as well. 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 compared to one in a relatively clean environment. We highly recommend that you check on 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 recommended by the manufacturer. If it’s dirty, clean it — it’s perfectly safe as long as you’re using the right 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 does come in handy, you also shouldn’t rely on it entirely. As mentioned above, frequent use of the appliance 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 begin to 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.

Keeping It Clean

Permanent or washable HEPA filters are excellent choices for when you want to save money on running your appliance. Replacing disposable filters can become way too expensive in the long run, which is why many opt for reusable.

Cleaning a HEPA filter is easy, but you must check whether you have a washable or permanent filter first. Permanent filters should only be dry-cleaned, meaning with a vacuum or brush. Washable filters, though, are safe to be rinsed with water.

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About the Author

Matthew Sullivan

Matthew is a freelance writer with several years of experience in DIY and HVAC. For as long as he can remember, Matthew has always found great pleasure in taking things apart and learning how to put them back together.