All About Activated Carbon Air Filters

When the air inside your home, business or office smells a little less than fresh it may be time to get an activated carbon air filter. Between cooking, pets, kids and the outside world the indoors can have strong odors that are hard to get rid of completely.

There’s one out-of-sight spot that could hold the solution to your problem. The air filter you use in your HVAC system can help remove particles from the air that cause odors to linger. But some air filters are better than others, and many people believe activated carbon air filters are the way to go.

What is an Activated Carbon Air Filter?

There’s a good chance you’ve never heard of activated carbon air filters until right now. It’s not much different from a conventional air filter, with a few extra features.

The most important distinction is that activated carbon air filters have a layer of carbon for the filter material. You may also see activated charcoal air filters, which is the same thing as activated carbon.

Advantages of the Best Activated Carbon Air Filter

In addition to removing odors, activated carbon filters can also clear the air of gases and volatile organic compounds (VOCs). This isn’t the same as removing air particles. Odors and other gases are molecules that are floating in the air. This isn’t what most air filters are designed to remove. However, these advantages do come with a drawback. Activated carbon air filters aren’t great at trapping pollen, dust, mold and other fine air particles. Allergy-sufferers may want to use a pleated MERV 13 air filter instead or invest in a few true HEPA portable air purifiers to use alongside carbon air filters.

How Do Activated Carbon Air Filters Work?

An activated carbon air filter doesn’t work like other air filters. The layer of porous activated charcoal is able to adsorb gas molecules and large air particles. Adsorbing means that instead of soaking in the molecules stick to the carbon surface. The activated charcoal is so powerful it can trap cigarette smoke. Once stuck in the carbon, odors are neutralized.

The carbon is a form of charcoal, either coconut, wood or coal. To get very scientific, carbon is carbon atoms that are connected together in a latticework. The carbon used in air filters has been activated. That means the carbon material has gone through a process that makes it more porous and therefore able to capture more molecules. The carbon may also undergo a chemical process to improve its ability to filter certain air pollutants.

An infographic of activated carbon air filters.

But that porous surface also allows fine particles to slip through and keep circulating through the air. You’ll need to decide if odor and gas removal is more important than removing allergens and mold.

It’s important to note that not all active carbon air filters are created equal. The more carbon that’s used the longer it will last and the more it can pull molecules out of the air. Look for filters that use at least 5 pounds of carbon. You’ll also want the activated carbon air filter to be as thick as possible. The longer the journey is through the filter the more likely molecules are to stick.

All homeowners should also understand that activated carbon air filters do not clear the air of carbon monoxide. If there’s the potential for exposure carbon monoxide detectors should be installed.

Does a DIY Activated Carbon Air Filter Work?

We admire homeowners that want to roll up their sleeves and do things on their own. But not every home project is DIY appropriate.

You may have seen videos on YouTube about how to make your own activated carbon air filter at home. But what they don’t tell you is it requires a 5-gallon bucket or large box. To make a DIY activated carbon air filter you need a container that is open on the sides so that air can be pulled in. If using a 5-gallon bucket holes must be cut into it. Around four pounds of activated carbon is held in a center container and there’s a fan affixed to the lid. The fan draws air into the container and pushes it back out of the top.

An image shows a hand touching a DIY carbon air filter.

Activated carbon air filters aren’t cheap, but making your own isn’t either. There are also ongoing costs because the activated carbon will need to be replaced.

If you’re considering a DIY option because sizing is an issue you’re much better off using a manufacturer like Filterbuy that can create the custom air filter size you need. This will give you a precise fit with a lot less hassle.

How to Clean an Activated Carbon Air Filter

Like other air filters, activated carbon air filters must be cleaned or replaced once the surface area is covered. At that point there are no more adsorption points where air molecules can adhere.

Instead of neutralizing odors, when an active carbon air filter needs to be replaced or cleaned it emits a foul odor. It can also begin releasing gas molecules that were captured as new molecules flowing through push them loose.

How long before an activated carbon air filter needs to be changed or cleaned depends on a few factors like:

  • How much carbon it contains
  • The thickness of the air filter
  • How much its used
  • The amount of pollutants in the air

If you’re not sure how often you should clean your activated carbon air filter check out the manufacturer recommendations. This will give you a general guideline. Some experts recommend cleaning this type of air filter every 2-4 weeks and replacing it after a few months of use.

When it’s time to clean your activated carbon air filter, there are a few ways to clear it of pollutants.

  1. If the air filter is labeled washable you can wash it following the manufacturer’s directions.
  2. Some activated carbon air filters can be vacuumed.
  3. You can sit an activated carbon air filter in the sunlight for 2-3 hours. However, this can only be done a few times before the air filter needs to be replaced.

Activated carbon air filters are more expensive than conventional air filters so regular cleaning is a good idea. It will help improve efficiency and longevity so you get more out of every activated carbon air filter.

READ MORE: Which Air Filter Should I Choose