What is a HEPA filter? - The most complete guide

In this guide, we explain everything you need to know about the most common HEPA filters, their benefits and how to choose the right filters for your home by differentiating between real and fake filters.

What is a HEPA filter?

HEPA (High Efficiency Particulate Air) is a type of high efficiency air filter that filters out particles and irritants that can cause problems for allergy sufferers and meets regulatory standards.

Characteristics of HEPA filters

A HEPA filter is a type of mechanical air filter that passes air through a fine mesh that traps harmful particles such as pollen, pet dander, dust mites and tobacco smoke.

HEPA filters are available in most air purifiers.

Air purifiers are devices that, for a very affordable price, can greatly improve your quality of life. They are often overlooked, but in a world where thousands of people die every day from air quality problems, we should have at least one air purifier in our homes.

These are small, portable units that work perfectly well in individual rooms. If you are considering a HEPA filter purifier , find out how much air it can clean and make sure you buy one that is large enough for the room you plan to use it in.

The best room to install one is the one where you spend the most time (usually the bedroom or living room). You can find HEPA filters on Amazon and at most appliance stores.

Vacuum cleaners with a good HEPA filtration system can trap up to 99.97% of dust and dirt particles. These vacuums release less dirt and microscopic dust mites during use. Some people report that allergy symptoms improve after using this type of vacuum. Check out my guide to the best corded vacuums to see which vacuum is right for you if you suffer from allergies.

Types of Filters

HEPA filters are unique in that they meet certain regulatory standards. In the U.S., they are governed by the U.S. Department of Energy standards, and in Europe, they are currently governed by the UNE-EN 1822-1:2020 standard implemented in Spain by the Spanish Association of Standardization.

These filters are known as absolute filters and are classified into 3 main types according to their efficiency:

EPA: High efficiency filters.

HEPA : Very high efficiency filters. Quality vacuum cleaners and purifiers generally incorporate this type of filter.

ULPA: Professional filters for ultra fine particles. They are used in clean rooms, operating rooms, pharmaceutical and food industries, microbiology, filtration of hazardous substances, heavy metals, carcinogenic dusts and other similar industries where sterile environments are required for specific purposes.

As you can see, HEPA filters are the most widely used filters in the appliance market and are more than sufficient for the needs of the average user.

True HEPA Filters vs. "Type" HEPA Filters.

If you are looking for a vacuum or purifier with a HEPA filter, make sure it has a true HEPA filter. Some units try to mislead with descriptions such as "HEPA filter type".

According to the U.S. Department of Energy, by definition, a HEPA filter can capture up to 99.97% of ultra fine particles as small as 0.3 microns.

Fact: One mirca (or micrometer) is equivalent to 0.001 millimeters.

HEPA filter regulations mean that consumers can be assured that all HEPA filters on the market have the same level of performance.

The difference between a true HEPA filter and a typical HEPA filter

The difference between a true HEPA filter and a "typical" HEPA filter.

With these standards, it is easy to know that any filter that performs below the above mentioned data is not a true HEPA filter.

How does a HEPA filter work?

When a HEPA air purifier is placed in a room and turned on, it begins to draw in air. As particles pass through the purifier, they begin to interact with the HEPA filter.

As the air passes through the filter, the larger particles are absorbed by the filter and clean air passes through.

HEPA filters can be permanent or removable. A disposable HEPA filter is made of a dense paper-like material. It degrades over time and must be replaced.

On the other hand, a permanent HEPA filter will likely last the life of the purifier, but not without some maintenance.

Many vacuums have HEPA filters inside the unit itself, which helps remove fine debris during cleaning. The Dyson V11, V10, V8 and V7 include a washable HEPA filter.

Benefits of HEPA filters

Widely available on the market. HEPA filtration is one of the most common types of filtration in today's air cleaners. If you are looking for a product that is proven to provide cleaner air, a HEPA filter air purifier may be a great option for you.

They capture a wide variety of particles. Since a true HEPA filter is capable of capturing up to 99.97% of particles, it is very effective at purifying the air. This includes airborne particles such as pet dander, pollen and dust mites.

Can I wet the HEPA filter in my vacuum cleaner or air purifier?

Always read the manufacturer's instructions, but in principle, most vacuum and air purifier filters can be washed with water without any problems. Be sure to let it dry before putting it back in the unit.

How do I clean the HEPA filter? Cleaning Instructions

Preliminary note: Read the instructions for your unit for applicable specifications.

Carefully remove the HEPA filter from your unit so as not to spread too much dust on the floor.

Rinse the pleated side of the HEPA filter under a low-pressure hot water faucet.

Hold the filter so that the water flows parallel to the pleats.

Hold the filter at an appropriate angle and gently rotate it so that the water flows through the pleats in the opposite direction.

Repeat this process until you see that the filter is clean.

Carefully shake out the water and allow it to dry completely before putting it back in the unit.


Do not clean HEPA filters with a brush as they are delicate and can be easily damaged.

Do not worry if the filter does not return to its original color after washing. The important thing is that it will have regained its filtering capacity.

How much space can a HEPA filter purifier clean?

HEPA filter air cleaners come in many shapes and sizes and have a variety of functions.

Depending on the size and price of the air purifier , these types of air pur ifiers can cover an area of 4.5 to 120 square meters.

Compact HEPA air purifiers: These purifiers are small, portable and designed to be taken anywhere you go. They can be placed on furniture and shelves and are generally cheaper and lighter, which means the filtration coverage area is smaller. (Average coverage area: 4.5 - 18.5 square meters).

Medium HEPA Air Purifiers: Medium HEPA air purifiers are slightly larger and are designed to purify medium to large rooms. While they are convenient to move from room to room, you won't usually be able to place them on tables or shelves.

However, their larger size usually means higher filtration power (average coverage area: 18.5 - 46 square meters).

High Coverage HEPA Air Cleaners: High coverage HEPA air cleaners are designed to cover entire floors without partitions or very large rooms. They are generally larger in size and incorporate larger, more powerful HEPA filters. (Average coverage area: 60 - 120 square meters).

The filters in these purifiers can have a longer life because their larger surface area allows them to take longer to saturate.

Are HEPA filters really effective?

Using a HEPA filter purifier in your home is able to remove most of the particles in the air that can aggravate allergies. However, it is not only airborne particles that can cause allergies or affect air quality. There are many more in carpets, bedding and curtains, as well as on furniture and tables. It is therefore important to keep these areas clean. It's also important, whenever possible, to get rid of the source of allergens and irritants (although it seems obvious, the only effective way to keep tobacco smoke out of your home is to not smoke).

Air cleaners with HEPA filters are really effective, but they may not be enough on their own. It's best to combine them with a plan to remove harmful particles from your home. Here are some tips:

Vacuum frequently with a good vacuum cleaner that meets quality standards.

Replace carpeting with hardwood, tile or vinyl floors.

Keep pets out of the room where you sleep.

Change bedding frequently and wash sheets in hot water.

Replace curtains with roller blinds.

Use dust mite covers on mattresses and pillows.

We invite you to read this article from porch about transforming Your Home into an Allergy-Free Haven with Smart Gadgets.

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