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HEPA Filters – What are those? How they work? Benefits? [Guide]

HEPA filters guideHigh-efficiency particulate air (HEPA) filters are a type of mechanical air filter designed to trap even the tiniest particles of dust mites, pollen, pet dander, and even tobacco smoke.

It can allegedly clean better than all other filters – the main reason it comes with a rather hefty price tag.

But what is precisely the hype about? What do HEPA filters do, and does your vacuum really need one? Let’s find it out.

All About HEPA Filters

What is a HEPA filter?

A HEPA filter is a type of air filter that can theoretically remove over 99.90% of dust, pollen, microorganisms, mold, and other airborne particles with a size of 0.3 microns.

Larger particles are trapped with even higher efficiency, a feature that makes them one of the most sought-after filters on the market.

According to EPA, HEPA filters are made from a variety of materials tangled together randomly and compressed into paper-like sheets.

Materials range from vegetable fibers to synthetic foams, coarse glass fibers, expanded metals, and even coated animal hair, so it is hard to determine their exact composition.

That said, you can rest assured all HEPA filters are hypoallergenic.

Sometimes, manufacturers also add other elements to HEPA filters, including antimicrobial silver linings, activated carbon to reduce or remove odors, as well as pre-filters to screen out larger particles and increase HEPA filters’ lifespan, especially for filters installed in vacuum cleaners.

How do HEPA filters work?

HEPA filters work like all other mechanical filters – they trap air contaminants in their complex web of fibers. Larger contaminants usually collide with the filter and remain blocked due to their size.

In comparison, smaller contaminants are trapped as they travel through the filter. Air circulating through the filter also dissipates the tiniest particles, which will eventually collide with fiber and remain trapped.

Are all HEPA filters the same?

Cutting a long story short, no.

Note: Not all HEPA filters are the same.

Not only may there be significant differences in composition and utilization, but we must also distinguish between genuine HEPA filters and HEPA-type filters.

1) True HEPA filters

Are HEPA filters that have been tested and meet a specific standard. Only tested filters can be called HEPA; however, nothing keeps manufacturers from naming their untested filters HEPA-type or HEPA-like.

Thus, you should pay particular attention to the label when buying an allegedly HEPA vacuum cleaner.

To ensure the filter is authentic HEPA, check the serial number and test results that must be printed on the filter – a true HEPA filter must be proven to trap at least 99.97% of particles of 0.3 microns.

2) HEPA-type filters

Are manufactured in a similar fashion to true HEPA filters and even look the same to the naked eye. However, these filters are not required to meet any specific standards and may or may not trap dust and allergens efficiently.

Indeed, many HEPA-type filters can only trap around 85% of all particles, and most fail to trap particles smaller than 1 micron.

Since they are not authentic HEPA, these filters don’t have a serial number and printed test results.

HEPA-type filters: Why does it matter?

While most healthy individuals won’t notice a real difference when cleaning with an authentic HEPA or HEPA-type filter, using a non-HEPA filter type may affect people with allergies.

Although there have been surprisingly few studies conducted to evaluate the impact of HEPA filters on air quality, in a paper published in the American Journal of Respiratory and Critical Care Medicine, scientists demonstrated that genuine HEPA filters positively impact a room’s air quality.

Sure, simply using a HEPA filter won’t treat asthma or allergy symptoms. Still, they do an excellent job cleaning and getting rid of most allergens.

As mentioned above, newer HEPA filters may have antimicrobial functions or contain active carbon that traps odors and some chemical fumes.

What are the disadvantages of HEPA filters?

Like anything else, HEPA filters also have some disadvantages.

Perhaps the biggest one is the filter cost. Vacuum cleaners with genuine HEPA filters tend to be more expensive than non-HEPA models.

Plus, spare filters are relatively expensive.

Add in the fact that not all HEPA filters are washable, and they might be a costly affair in the long run.

Are HEPA filters washable?

In a nutshell, no. Some vacuum cleaners come with washable or “permanent” HEPA-type filters (note that we didn’t say true HEPA).

These filters can be rinsed with tap water to wash off embedded dirt and grime, but you can’t expect them to trap most allergens.

Cleaning the filters often damages the structure of the fibers, so the more you wash it, the least effective it will be.

Because there is no standard for washable filters, no true HEPA filter is washable. You can clean them if you really want, but keep in mind that you won’t get the same performance.

If you decide to clean your HEPA filter:

  • Only wash it with tap water. Detergents may damage the structure and are also difficult to rinse off thoroughly.
  • Let the filter air dry completely before using it again. Moisture trapped inside the filter creates the perfect environment for mold and mildew to grow.
  • Never clean your filter indoors, especially if you or someone in your household suffer from allergies.

How often do I have to replace your vacuum’s HEPA filter?

Whilst HEPA filters are more expensive than other filter options, the good news is that you don’t have to replace them too often.

It goes without saying that there isn’t a fixed period of time – how often you have to replace the filter depends on how often you use your vacuum cleaner and whether you’re making it run in a domestic or commercial setting.

  • For home use, you should replace the HEPA filter once every two years. Even if you use the most expensive filter, you still won’t break the bank.
  • For commercial use, you should replace the filter at least once every six months. You should inspect the filter regularly and change it more often if heavily soiled.

Is there anything better than a HEPA filter?

Yes. If you’re concerned about allergies or asthma, you should probably get a ULPA vacuum cleaner. ULPA filters can trap particles as small as 0.1 microns.

Note: ULPA stands for ultra-low particulate air.

ULPA filters are made from similar materials and look like HEPA filters; they should be used, maintained, and replaced in a similar way.

The main difference between the two is that ULPA filters can block around 99.99% of airborne contaminants, slightly more than the 99.97% efficiency of a HEPA filter.

That said, ULPA filters are more expensive than HEPA, and most people will do just fine with a HEPA vacuum cleaner.

How to know if your HEPA filter is dirty?

Examining and changing the vacuum filter regularly is essential if you want to clean your surfaces properly and keep the vacuum cleaner in good working conditions. A clogged filter will have little impact on pollutants, and it may also damage the machine.

The easiest way to tell if your HEPA filter is dirty is by looking at it. Simply open the vacuum cleaner and assess the state of the filter. Clean HEPA filters are white or a light yellowish shade.

If the filter turns a dark shade of grey and there is a lot of debris trapped within it, you should clean or change it.

Do HEPA filters smell?

HEPA filters are made from non-toxic plastic materials and don’t have any particular smell. New HEPA filters may have a faint scent of glue that usually goes away after one or two uses of your vacuum cleaner.

However, if the filter has a lousy chemical odor, it probably isn’t a true, high-quality HEPA filter.

Suppose the filter didn’t have any smell initially, but you notice it has developed an unpleasant, musky scent over time.

In that case, it could be that mold and mildew have started to grow inside the filter. If this happens, it is advisable to replace the filter with a new one as soon as possible, especially if you have asthma or airborne allergies.

Conclusion – Are HEPA vacuum cleaners worth it?

If you suffer from allergies or any other respiratory conditions, a HEPA vacuum cleaner can help you minimize dust, pet dander, mold spores, and other common allergens in your home.

You may also want to go for a HEPA vacuum cleaner if you have small children that crawl all over the floors.

However, be attentive here; keep in mind that a HEPA filter only works if it’s an authentic HEPA, and you replace it as often as instructed. Otherwise, you may do just as well with a regular, cheaper vacuum cleaner.

Want to find out more? Here are a few important resources:

How to clean HEPA filters: Tips and tricks for cleaning HEPA-type filters.

How to know when to replace a HEPA filter: Step-by-step instructions to examine and change HEPA filters.