Portable home air purifier filters can be a tricky component to clean. If not cared for or cleaned correctly, their filtration performance can be severely diminished. This is particularly true for non-washable HEPA, HEPA-type, and activated carbon filters.
In this post, you’ll learn how to clean the HEPA-type filter, True HEPA filter (Not a good idea!) activated carbon filter, and prefilter of a typical Holmes air purifier.
Most Holmes units use a washable foam pre-filter. You can toss this reusable filter in the sink or tub and wash it with regular dish soap and warm water.
If your unit features a permanent filter (not a True HEPA filter), you can vacuum it with a suitable attachment. The dust brush attachment of your carpet vacuum cleaner is the right tool for the job.
As for the odor filter and True HEPA filter, don’t get them wet. Instead, replace them according to the manufacturer’s recommendations. While you could use a vacuum’s dust brush attachment to give a charcoal filter a light clean, it’s best to replace it when the time comes.
I recently watched someone on YT who actually washes their True HEPA filter and said it works for them! I’ll tell you more about this interesting story later in this guide.
Decent Holmes True HEPA air filters can be expected to last between 6 to 12 months. The company’s pet odor filters need to be replaced after every 2-3 months. It all depends on the actual state of your indoor air quality.
Can You Wash Holmes Air Purifier Filters?
If it’s a HEPA filter, you shouldn’t wash it. Because washing can substantially reduce the filtration efficiency of a HEPA filter, cutting it by up to 50%. Instead, replace the filter.
What if money is tight and you can’t buy replacement filters at this time? In that case, you can use short bursts of compressed air to blow out trapped materials off of the HEPA filter. Just don’t get the filter wet.
Don’t have a compressor and still want to clean your Holmes HEPA filter? Remove the filter and shake it a little before putting it back in. But understand this won’t get the filter working as efficiently as before. It just buys you a few days in most cases.
I DO NOT recommend washing True HEPA filters, especially if you have difficulty breathing. If that’s you, stop reading and go buy a Holmes replacement HEPA filter.
Also, you shouldn’t wash Holmes activated carbon filters. But it might be possible to increase the longevity of these odor filters to some extent through vacuuming.
Here’s good news! Holmes permanent filters (HEPA-type) and prefilters can be cleaned (not washed).
Let’s now learn…
How to Clean Holmes Prefilters
Holmes air cleaners typically come with a washable foam prefilter. It’s called a prefilter because it captures larger debris such as pet hair and dust clumps before they stream to the main filter. The manufacturer recommends cleaning these washable filters at least once every month.
Steps for Cleaning a Holmes Washable Prefilter
1. Turn off your Holmes air purifier.
2. Open the unit’s front cover.
3. Remove the washable foam pre-filter.
4. Examine the prefilter to decide if it needs a clean.
Inspect the prefilter every 3 weeks to see if it needs cleaning:
- If the prefilter seems torn or dilapidated in some way, replace it.
- If it isn’t very dirty, give it a light shake before putting it back in.
- If there’s a ton of pet fur, fabric lint, and other visible materials on the prefilter, clean it. How? See steps 5 through 7 below.
Pro Tip: Put on a decent mask before shaking the dusty prefilter. The same goes for other types of filters.
5. Add some mild powder soap/liquid soap into warm water in a bucket or sink and wash the soiled prefilter. Use your hands, a soft cloth, or a soft-bristled brush to gently rub the prefilter.
6. Rinse the soap out of the prefilter using warm water.
7. Finally, place the rinsed pre-filter on a terrycloth towel to quicken drying. Alternatively, air out the prefilter in the sun for roughly 15 minutes. But if the weather isn’t conducive, turn on a fan. Once the prefilter dries up, reinstall it.
What Not to Do
- Don’t chlorine-bleach the prefilter.
- Stay away from harsh chemicals.
How to Clean Holmes Permanent Filters (HEPA-Type)
By permanent filter, I mean Holmes’ HEPA-Type filters. Permanent filters, just like True HEPA filters, shouldn’t be washed. And no, permanent HEPA filters don’t last an entire lifetime. At some point down the road, you’ll have to replace the permanent filter. I believe they call them permanent to lure in folks who obsess about saving money.
The filter-clean indicator for the permanent/main filter of Holmes air cleaners comes on 90 days after the previous clean. But if you notice a sharp decline in the medium’s filtration performance, you can definitely clean it sooner.
Steps for Cleaning a Holmes Permanent Filter
- Turn off the ionizer & purifier.
- unplug the purifier.
- Pull the tab on the inlet grille to access the permanent filter for inspection.
- If the permanent filter isn’t too dirty and filtration performance hasn’t taken a hit, shake it a little and reinstall it.
- If it’s noticeably dirty (it’s always dirty after 2-3 months of regular use if the unit is actually working), use the dust brush attachment of your vacuum cleaner on it.
What’s the correct way to vacuum a permanent HEPA filter? Give both sides of the permanent Holmes filter a few passes to pick up the dirt and debris hiding in its pleats.
The filter may get discolored after vacuuming it multiple times. But discoloration isn’t a sign of lost efficiency according to Holmes. So, put the cleanable filter back in and crank the unit up.
What Not to Do When Cleaning a Holmes Permanent Filter
1. Don’t wet the filter.
2. Never use harsh cleaners.
3. Don’t use detergents, cleaners, or bleaches on these filters.
How to Clean a Holmes Carbon Filter
Activated carbon filters, sometimes referred to as charcoal filters/odor filters are designed to capture what HEPA filters don’t remove efficiently. The best charcoal filters can remove wildfire smoke particles, VOCs (to some degree), and even exhaust fumes (to some extent).
Holmes recommends replacing their carbon filters every 3 months.
So, how do you clean a Holmes odor filter? Holmes warns against washing their odor removal filters. Fortunately, you can light-clean this filter using a vacuum.
Steps for Cleaning a Holmes Carbon Filter:
1. Turn off the ionizer and unit.
2. Unplug the device.
3. Use a vacuum to light-clean the filter if you need to. Otherwise, replace the carbon filtration filter. Be sure to replace this smell sieve sooner if your indoor air quality needs constant attention. But how do you vacuum a Holmes carbon filter? It’s easy. Attach a crevice tool onto your vacuum cleaner and give each side of the charcoal filter a few side-to-side passes.
4. Once done, replace the odor filter and that’s it.
What Not to Do When Cleaning a Holmes Odor Filter
- Never wash your Holmes pet odor filter with water.
- Never use a damp/wet sponge or cloth.
Can You Really Clean a Non-washable Holmes HEPA Filter?
I recently bumped into an industrial air filtration expert called Scott O’Malley, while watching a DIYer on Youtube. In the video, the DIYer encouraged people to clean their HEPA filters instead of throwing them away.
That sounded like a really good idea. Who wouldn’t want to contribute less waste to the world’s ever-expanding landfills? The person believes that manufacturers insist on HEPA filter replacement because that’s where they make the bulk of their money.
But according to O’Malley, cleaning HEPA filters is plain dumb, and here’s why: Disposable HEPA filters are made of two types of fibers: 80% polyester and 20% cellulose blend. Manufacturers tightly weave these fibers into an intricate webby structure designed to trap particulate matter that’s smaller than the ultra-small “holes” between the fibers. Finally, an efficiency-enhancing ePTFE coating is laid on the filter. ePTFE stands for Expanded Polytetrafluoroethylene.
When you rinse your Holmes HEPA filter under running water at the kitchen faucet, the force of the water easily separates the woven fibers. And this weakens the structural integrity of the filtration media. This is why a frequently washed HEPA filter becomes less effective over time.
What If You Still Want to Clean Your Holmes HEPA Filter?
Well, it’s your filter. But if you must clean a non-washable HEPA filter, the best way to get trapped debris and dirt out of the filter is to use a compressor according to Scott O’Malley. Quick bursts of compressed air at a PSI of 50-60 should be sufficient to dislodge dry debris and dirt. But the expert didn’t at any point say that cleaning a HEPA filter this way prolongs its lifespan.
Here’s the correct way to clean a non-washable HEPA filter using compressed air: Position the compressor on the cleaner side of the filter and start blowing toward the dirtier side. A compressed air backflush is the best alternative to the seriously destructive rinse-the-filter-with-water strategy.
How to Clean a Holmes HEPA Air Purifier Filter
Some Holmes air purifiers use HEPA-Type filters while others use True HEPA filters. If your Holmes purifier runs a True HEPA filter, the filter should remove at least 99.97% of particles 0.3 microns in size. In comparison, HEPA-type filters have a 99% efficiency when removing particles with a diameter of 2 microns.
A True HEPA filter such as the Holmes HAPF300AP aer1 True HEPA Performance Plus Filter theoretically captures air contaminants better than HEPA-type options.
Some People Actually Wash Their HEPA Filters!
The YT DIYer in the video mentioned above cleans their True HEPA filter as described below. And they claim they’ve never bought replacement filters for two decades! They further claim that the filter’s after-cleaning performance wasn’t adversely affected.
This isn’t how I clean my HEPA filters. My wife has allergies, so yeah. And I do not encourage anyone to try this creative HEPA filter cleaning method. Watch the video and decide whether you really want to clean your highly efficient Holmes HEPA filter that way.
Here’s that DIYer’s method:
Step 1: Remove the HEPA Filter of Your Holmes Purifier.
Most Holmes purifier models come with a removable panel in the front of the unit. Unclean air streams in through this front air vent. Clean air comes out through the top. So, remove the grille to access the HEPA filter.
Step 2: Run Enough Warm Water Water into a Sink.
Take the HEPA/HEPA-type filter to the sink and open the hot-water faucet. Then, add a little dishwashing soap to the warm water. Next, immerse the filter into the warm soapy water.
Note: close the faucet before submerging the filter to prevent the force of the water from hitting the filter directly. Soak the media for 10-15 minutes to allow the soapy solution loosen up the dirt. Then, give the filter a few quick but gentle movements into and out of the water. This lets the water flow through the filter, which lightly agitates it.
Step 3: Rinse the Filter With Warm Water.
Remove the filter from the dirty soapy water and set it aside. Then, let a reasonable amount of clean warm water run into the sink before re-immersing the filter. Repeat the motions described in step 2 above until the filter is clean. You may have to rinse twice to get all the soap out.
Step 4 (Optional): Sterilize the Filter With Bleach (Not Recommended)
You can skip this step, but not if you want to sterilize the media before drying it out. To sterilize the filter, add a little bleach to a half sinkful of warm water. Then, dip the filter into the water/bleach solution. Bleaching the media supposedly won’t destroy it, but I strongly suggest that you skip bleaching your HEPA filter. The manufacturer holds the same option.
Step 5: Lay the Clean Holmes HEPA-Type Filter on a Dry Towel
Get the clean filter out of the soapless water (or water/bleach mix if you didn’t skip this step). Then, put the filter on a dry folded terry cloth towel.
The purpose of this step is to let the water in the filter wick into the dry towel underneath. Depending on the room’s temperature, the drying process takes about 30 minutes. You can also put the semi-dry filter back in and let the unit’s air circulation complete the drying process.
How to Clean a Holmes Purifier
You need: A piece of clean soft cloth, some water, and a pair of diligent hands.
Follow the steps Below to Clean a Holmes air purifier:
1. Turn off the appliance. Also, turn off the ionizer if your unit has this feature.
Failure to turn off the ionizer often generates a static charge. And you’ll notice this static charge buildup at the outlet grille.
2. Unplug the device.
3. Dip a piece of clean cloth into clean soapless water and wring the water out.
4. Give the outside surface of the purifier a quick wipe-down to take care of the dust and dirt.
5. Turn on the ionizer if you need to and plug the unit back into the outlet.
What Not to Do When Cleaning a Holmes Purifier
1. Don’t start cleaning the unit before you’ve turned off both the ionizer and unit.
2. Don’t use any kind of household detergent to clean the purifier’s housing.
3. Don’t use any of the following cleaning supplies: gasoline, furniture polish, glass cleaner, thinner (according to Holmes).
4. Don’t let water get inside the appliance. Because water, electricity, and the motor of a Holmes air cleaner were never meant to become the best of friends!
How to Clean the Inside of a Holmes Air Cleaner
If you decide to clean the inside of your Holmes air-purifying device, follow the steps below:
1. Power off the device.
2. Unplug the room cleaner.
3. Remove the inlet and outlet grilles.
4. Give the unit a quick wipe-down using a clean (it should be dry), soft microfiber cloth.
Wrapping It All Up
Different Holmes air filters are cleaned using different techniques. To clean permanent Holmes filters, vacuum them with a soft-bristle vacuum attachment. And if you must clean the charcoal filter, use a vacuum’s crevice tool.
Clean washable foam prefilters in warm soapy water.
As for True HEPA and activated carbon filters, it’s best to replace them once they get too dirty. Wetting a True HEPA filter isn’t recommended unless you’re OK with substantially decreased filtration performance. Or unless you like buying expensive replacement filters.