HEPA Filter vs Activated Carbon Filter

HEPA filter vs activated carbon filter: which filter type do I need in my baby room? It’s not possible to do a shoulder-to-shoulder filtration performance comparison between a HEPA filter and an activated carbon filter.

Related: Best Air Purifiers for the Nursery

These are two different kinds of air filters designed differently and meant to do achieve different air filtration goals.

If you’re wondering which is better between HEPA filters and Carbon filters, you’re asking the wrong question. Both filters are good, but they serve different purposes. And chances are that you need both types of filters rather than one or the other.

What’s an Activated Carbon Air Filter and How Does It Work? 

An activated carbon filter is the quintessential odor and VOCs removal solution. This odor filtration media is created using highly porous charcoal. Unlike a HEPA filter which is a mechanical filter, a carbon filter is a chemical filter.

A charcoal filter removes household smells and gaseous pollutants such as paint fumes and exhaust fumes through a chemical mechanism known as adsorption. This chemical process causes filtered air contaminants to stick onto the extremely large surface area of the sorbent/filter and stay there.

Adsorption works completely differently than absorption. When absorption takes place, the substance being absorbed doesn’t become in any way chemically bonded to the absorbent. Think of how a sponge soaks up water or spilled stuff such as liquid stains. This is a perfect example of how absorption works.

But during adsorption, the adsorbed substance attaches chemically to the bazillion micropores found in the adsorption site. 

When it comes to removing odors and Volatile Organic Compounds, you don’t want the air to flow through the activated carbon filter too fast. An optimal airflow speed makes sure that the airstream has enough dwell time so that the filter media can remove a decent amount of contaminants.

How is an Activated Carbon Filter Made?

Activated carbon/activated charcoal comes from a variety of carbon-rich materials. Carbon filter manufacturers use materials such as wood, coconut, and coal to produce this odor-adsorbing filter. Coconut carbon air filters tend to be better at odor and VOC removal than filters made from wood or coal.

Carbon filter manufacturers blow hot steam through the carbonaceous material to “crack it”, creating millions of super-small pockets. These many tiny pockets tremendously extend the filter media’s total surface area. For example, just 1 gram of activated carbon filter amounts to a surface area of between 10,226 and 21,528 sq. ft. according to ScienceDirect. 

Activating ordinary carbon chiefly aims at increasing the media’s overall microporosity. This increased surface area becomes storage where adsorbed chemical pollutants stay until you replace the filter.

This filter types removes toxic chemical pollutants including xylene, toluene, benzene, and formaldehyde.

High-quality activated carbon removes gaseous pollutants and odors exceptionally well. This filtration media is the surest bet when it comes to tackling lingering kitchen odors, pet odors, Marijuana smoke, and stinky cigarette smells.

What is a HEPA Filter and What Makes it Special?

According to the Environmental Protection Agency, a HEPA filter should have a demonstrable minimum filtration efficiency of 99.97% in catching airborne particles sized 0.3 microns in diameter. Don’t confuse HEPA filters with HEPA-type filters because they’re different. An earlier post published here on Kiddofreedom explains the differences and similarities between HEPA filters and HEPA-style filters. 

Are HEPA Filters the Same as Activated Carbon Filters? 

No, HEPA filters aren’t the same as activated carbon filters. HEPA filters mostly capture particulates or solid air contaminants while activated carbon filters focus on odor and chemical compounds elimination. These filters are typically used in industrial air cleaning systems and standalone units for home use.

Activated carbon filters are more versatile and are used in both air purifiers and water purifiers. In air purifiers, carbon filters help battle different kinds of odors.

In water purification systems, Granulated Carbon Filters (GAC) clean up impurities including Volatile Organic Compounds, pesticides, chlorine, hydrogen sulfide, and nitrates. When the filtration process completes, the water is odorless and tastes better.

Do Activated Carbon Filters Really Work?

Yes, they do. Traditional societies in different parts of the world have used common carbon to purify water for thousands of years.

Historians tell us that the Egyptians were the first known civilization to use carbon for water treatment more than 1600 years ago. Egyptians also used carbon for a variety of medical purposes, notably in tackling odors from festering wounds.

Other early adopters of the carbon filtration technology were sailors. Sailors used carbon to keep water fresh and safe for drinking throughout the months-long voyages. To do this, they coated the inside of water vessels with charcoal.

These days, homeowners and apartment livers turn to activated charcoal to adsorb all kinds of household smells. If you live with a tobacco-loving dear one, politely ask them to stop lighting up their cigars inside the house.

As for any lingering tobacco smell in the house, you can always use an activated carbon filter to adsorb it. Stubborn secondhand tobacco smoke can cause serious problems if not dealt with.

But are activated carbon filters able to remove carbon dioxide? Well, charcoal filters are pretty limited in terms of removing carbon dioxide gas. I suggest that you install a carbon dioxide detector so you can monitor your home’s CO2 levels like a pro.

One study suggested that modifying activated charcoal in some ways can increase the filter’s adsorptive ability for carbon dioxide. Who knows,  maybe these filters might become exceptionally good at removing carbon dioxide and monoxide in the future.

Not All Carbon Filter Air Purifiers Are Great at Removing Odors and VOCs

If you think every air cleaner advertised as having activated charcoal is an awesome odor eliminator, you’re mistaken. Choose a purifier whose smell filter contains enough carbon. But how much carbon should the filter have? If it says 10 or more pounds of activated carbon, then that’s OK. Unfortunately, most manufacturers don’t state how much charcoal their smell removal media contains.

How Do I Know When to Replace Activated Carbon Filters?

In most cases, the only way to know it’s time to replace your activated charcoal filter is when it begins to give off a strange odor.

What else could cause this odd odor? The performance of an activated carbon filter may vary depending on the current prevailing conditions in your home. Changes in temperature and humidity can cause the filter to release some of the trapped organic contaminants back into the air.

Some compounds may not stick onto the surface of the media strongly enough. Such pollutants may get released in favor of those with a greater affinity for the sorbent.

Are Activated Carbon Filters Better Than HEPA Filters? 

Activated carbon air filters aren’t necessarily better than HEPA filters. But they perform certain filtration tasks better than HEPA. HEPA filter media are best at tackling microscopic airborne particles including tobacco smoke particles, wildfire smoke particles, household dust, tree & grass pollen, mold spores, pet dander, and more.

Note: HEPA filters have no ability to remove smoke, VOCs, and odors of any kind. That’s a job best left to activated charcoal filters. 

Activated carbon filters outperform HEPA filters in terms of removing gaseous or vapor-like pollutants. The best HEPA air purifiers for getting rid of car exhaust fumes, pet odors, paint fumes from DIY paint projects, and cooking smells feature a reasonably thick carbon filter.

Neither filtration system catches 100 percent of particles from contaminated indoor air though. It’s best to use these particle filtration technologies together in the same unit or in conjunction with your HVAC system.

Do HEPA Filters Contain Activated Carbon? 

Most HEPA filters today come with a layer of activated charcoal on one side. If the device you’re considering is described as a True HEPA air purifier, chances are it also offers carbon filtration. But it might be possible to find a dedicated odor remover that offers carbon filtration and no HEPA filtration.

In some air purifiers, the carbon filter and HEPA media are separate. With such units, you can replace each filter individually.

Others use 3-in-1 cartridge HEPA filters that offer 3-stage air purification. This 3-in-1 cartridge filter consists of a prefilter, a HEPA filter, and a carbon filter in the same media. With these combo HEPA-activated carbon filters, you can’t change one without changing the other. 

Should an Activated Filter Go Before or After the HEPA Filter?

In most cases, the HEPA filter goes into the air filtration chamber first followed by the charcoal filter. So, the charcoal filter stays in front of the HEPA filter in that case. And the prefilter sits closest to the cover. The prefilter traps larger debris. This adds to the other filters’ lifespan.

The charcoal filter may clip onto the frame of the prefilter or attach to the HEPA media. Often, you can peel off the charcoal media and replace it if necessary without replacing the other filters.

Activated Carbon Air Filter Lifespan: How Long Do They Last?

Activated carbon air filters naturally have a shorter lifespan compared to HEPA filters. Their lifespan sits anywhere between 2 and 3 months. Actual longevity depends on the pollution levels you’re battling. Fortunately, odor filters aren’t very expensive.

HEPA Filter Longevity: What’s the Filter’s Lifespan Look Like?

HEPA filters are pricier than carbon filters, but they last considerably longer. Most HEPA filters serve allergy sufferers for anywhere between 6 and 12 months. Better ones can last up to 24 months or even longer. In some top-of-the-line air cleaners, it can last up to 5 years!

HEPA vs Carbon Filter, Which Filter Type Should You Choose?

Well, that depends on your specific air cleaning needs and budget. If you’re looking for an affordable air filter for capturing mostly tobacco smoke and pet odors, get an activated carbon air filter.

But if particulates such as pet dander, dust, pollen, and mold spores are the most concerning contaminants in your home, definitely HEPA. But why use one when you could use both filters and get cleaner, fresher, healthier air?

Keep Air Your Filtration System Clean

No matter which filter you choose, keep it clean. Also, replace the filter when the time comes. Usually, that’s when its performance starts to decline (for HEPA). Or when you start noticing strange smells from your carbon filtration system. It’s critical to replace filters regularly for a pollution-free home.

How Do You Clean Activated Carbon Filters?

Changing this filter out when it gets saturated is best. But if you choose to clean it, well, clean it. If it’s not too thin that a vacuum’s suction would suck it up or even shred it, you could vacuum-clean it lightly. Use your vacuum cleaner’s dust brush attachment to clean each side of the charcoal filter.

Wrapping Up

I believe you now understand what the differences are between HEPA filters and activated carbon filters. Be sure the air purifier you’re eyeing has enough charcoal in the carbon filter, otherwise it’ll be lame at removing VOCs and odors. It’s rare to find air purifiers (at least portable room air cleaners) that use a HEPA filter and not an activated carbon filter. Most models use both filters at the same time.