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How long do activated carbon filters last?

Updated on November 15, 2023
Written by
James Booth
James has over ten years experience as a content producer and editor. He focuses on writing articles that are compelling, clear and, more importantly, helpful to the readers. He honed his research and copywriting skills working as part of NeoMam Studios, the parent company of HouseFresh.

The lifespan of activated carbon filters depends on several factors, lasting from three months to a year. 

It’s essential to replace your carbon filter when it has worn out because it won’t work effectively and remove pollutants such as VOCs. 

One fundamental way to tell whether your filter needs replacing is by smell. If you can detect a strange odor while the purifier is running and/or the smell is coming from the filter, it’s time to get a new one.    

While activated carbon filters can’t remove fine particle pollutants like HEPA filters can, they’re brilliant at eradicating strong odors and gaseous pollutants. Using a carbon filter helps to ensure the air you breathe is clean and fresh. 

One of the downsides, however, is that the filters don’t last forever, and you’ll need to replace them at some point. Yet knowing when to replace the carbon filter can be tricky and different for every user. 

Unfortunately, the answer isn’t cut and dried. What is clear is that, due to the adsorption process, every filter will eventually wear out. The filter cannot absorb more pollutants once the activated carbon bed becomes saturated.

Activated carbon filters can wear out in as little as 3-6 months or last a year if not more. 

It ultimately depends on how hard the filter works and how much you use your air purifier. 

We can break down three key factors:

1. The number of pollutants in the air
If your home is newly constructed or renovated, this will increase the amount of airborne VOCs. And if anyone smokes and/or there’s a lack of ventilation in your space, this will also cause the filter to become saturated more quickly. 

Equally, if you live in an area with high air pollution, for example, near factories, the filter will have to work harder to eliminate contaminants. 

2. The quality of the activated carbon filter
As mentioned earlier, the amount of carbon affects the filter’s lifespan. Filters containing 10 lbs or more will last significantly longer (and be more effective) than those containing less than 5 lbs. 

3. The size of the carbon filter
The size of the carbon filter must be proportional to the size of your home, room, or apartment. If the filter is too small for the space, it’ll have to work harder, impacting its longevity. Always choose a filter that’s appropriate for the area’s square footage. 

How does an activated carbon filter work?

Made from materials like coal and wood, activated carbon is excellent at eradicating odors and VOCs because it is highly porous and has a large surface area. This means it’s ideal for trapping gaseous pollutants.Essentially, when contaminated air passes through the filter, these pollutants become attracted to the activated carbon’s surface via adsorption. Note that this is different from absorption

But what is the difference…? Well, with adsorption, the contaminants stick to the carbon’s outside or surface. However, they get absorbed inside it, as if being soaked up by a sponge.

After the adsorption process has taken place, clean, purified air is then recirculated around your home.

There are two types of carbon filters: loose-fill and bonded. Here at HouseFresh, we believe that loose-fill is the most effective as it can adsorb and capture contaminants more successfully.

If you’re wondering how much-activated carbon a filter should contain, the answer is quite a lot! Choosing one with at least 5 lbs is advisable, as more carbon equals more efficiency. Another bonus is that they should also last a bit longer, which brings us nicely onto…

How to know when your activated carbon filter needs replacing 

It’d be great if the filter could tell you precisely when it needs changing, but sadly this isn’t the case. However, certain things will give you a clue; one is smell. This includes both the odor in your home and the filter itself.

If you can detect foul odors even while running the purifier, this is a sign that the carbon filter has become saturated and needs replacing. 

Yet if you can’t pick up anything noxious in your environment, you could try smelling the filter. Activated carbon filters that are working well usually give off a sweet smell, but if it’s a bit, well, strange, then it’s probably time to replace it.

To try this out, open your purifier and remove the carbon filter. Then hold the middle of the filter up to your nose and… breathe in. If it smells chemically acidic or sour, then get a new one.

The short answer: No, you can’t.

If you wash activated carbon filters, this will significantly inhibit and compromise their performance. 

Moreover, washing the filter could lead to mold growth if it isn’t dried thoroughly. 

So although you might be tempted to give it a wash, we advise always purchasing a replacement carbon filter.


It can be tricky to ascertain how long your activated carbon filter will last and when it might be time to get a new one. This is because its lifespan depends on various factors, such as the amount of airborne pollutants in your home and the quality of the filter itself.

A good carbon filter can last between 3-6 months. But if you’re aware that there’s a high level of contaminants in your space, or you start to pick up a strange smell, be sure to seek a replacement.


About the author

James Booth

James has over ten years experience as a content producer and editor. He focuses on writing articles that are compelling, clear and, more importantly, helpful to the readers. He honed his research and copywriting skills working as part of NeoMam Studios, the parent company of HouseFresh.