How to Select A Carbon Filter for a Grow Tent or Grow Room

A carbon filter is vital to any grow room. They are designed to remove strong odors and harmful gases from the grow room.

When it comes to finding a carbon filter for a grow tent or grow room, you might not be sure where to start. Choosing the right size carbon filter for a grow tent is so important.

That’s why we put together this guide to teach you how to pick the best carbon filter for a grow tent or grow room. No matter which one you choose, all of these units come highly rated.

4” carbon filters are the smallest option out of all the carbon filters available, but you still have plenty of options to choose from.

Quick Facts on Carbon Air Filters

  • If you’re on a budget, you might want to consider budgeting for a more expensive filter instead of settling for a cheaper option. The cost will be offset by the longer lifespan of the more expensive filter.
  • The equation to figure out which CFM level you need is the volume of the grow room divided by 3. You calculate volume by multiplying the length, width, and height.
  • Carbon air filters are safe, reliable, efficient, and effective at controlling odors.
  • Carbon air filters themselves do not require electricity.
  • Read the instructions carefully! Many manufacturers give recommendations on how to use or set up their filters.

Why Are Carbon Filters for Grow Tents So Special?

Carbon filters are filters made of activated charcoal intended to remove strong odors and harmful gases from the air.

Indoor grow rooms (or even small greenhouses, ) are a key to keeping grow room odors from spreading to the rest of the home because, while indoor grow rooms come with a lot of advantages, they can create intense smells throughout the whole house.

Air purifiers, gels, and odor-neutralizers may help keep bad smells from smelling, but they mask the scent. Carbon filters actually filter the odors from the air itself.

Personally, I would always recommend buying a carbon filter over any alternative. They work better.

However, they only work better if you choose the right one for your space. When selecting the correct charcoal filter for your grow rooms, you have to consider a few things:

  • What square footage area is it rated to cover?
  • The quality of activated carbon?
  • How long the filter lasts?
  • What parts come with the carbon filter?
  • Is the carbon filter portable?

First of all, you want a carbon filter that can cover your grow tent or grow room’s area without a problem.

Secondly, you want high-quality activated carbon when buying a carbon filter.

Typically this means buying a more expensive option. I find that the increased lifespan of the filter usually offsets the cost.

Cheaply made (and cheaply sold) options sometimes only last a couple of months. More expensive alternatives can last 1-2 years.

However, make sure you check even the most expensive options for the quantity of carbon used.

Some filters might claim to be carbon filters but barely contain any carbon. Their lifespan is EXTREMELY short.

Additionally, the more carbon they use, the more effectively they will filter the air.

It would be best if you also considered whether or not your choice comes with accessories.

I think that options that include a replaceable fabric sleeve or pre-filters are the best choice most of the time. Some fabric sleeves and filters are even machine washable.

Lastly, you may want to consider the portability of the air filter before purchasing. Portable carbon filters are more compact.

In my experience, that means that they run more quietly, and the carbon better absorbs any odors.

You’ll also want to make sure that any of these options can handle running 30-60 times an hour.

What Size Carbon Filter is Needed for a Grow Tent and Inline Extraction? 

Inline Extraction Fan

As discussed, choosing the right size carbon filter to cover your grow tent’s overall space is the most important deciding factor.

You NEED to get a filter that will match the area of your grow tent.

To buy the correct carbon filter size, you’ll need to calculate the grow tent’s volume or grow room. You can do that by using this formula below:


You then divide the volume by three to get the minimum recommended CFM for your space.

The CFM is the number used by carbon filter manufacturers to determine how effectively they filter spaces. To be safe, I purchase carbon air filters that cover 20% more than the CFM I actually need.

While that oftentimes isn’t necessary, there is no negative impact of choosing a carbon air filter that is technically too big for your room.

What is the Purpose of A Grow Tent Carbon Filter?

A carbon filter removes any odors and/or harmful gases from the air.

In a grow room or tent, that means a carbon filter is designed for odor control and to improve overall air quality.

Proper ventilation of quality air is an important part of growing healthy plants and getting maximum yields.

With any of the carbon filters (or carbon filter and fan combos), you’ll be able to set up a high-yielding, efficient grow tent and get the best results every time!

How To Set Up Carbon Filters in Your Grow Room or Tent

Carbon filters are usually pretty easy to set up.

Typically, they can be attached to ducting, rubber couplers, and rigid pipes.

My recommendation is to read the specific directions on your air filter to find the best way to set up your air filter.

You can’t go wrong if you follow the instructions!

How to Take Care of Your Carbon Filter

Setting Up Carbon Filter For Grow Room

Luckily, carbon air filters are generally pretty easy to maintain. They require minimal maintenance to work efficiently.

Changing the filter as soon as it becomes saturated is recommended.

Many air filters include directions on how often to switch out filters – which can be incredibly helpful, seeing as you shouldn’t base when to change the filter on the room’s smell.

However, for the air filter to work properly, even if correctly maintained, you must remember to provide proper airflow.

Proper airflow makes it, so the air passes through the filter and can be even more important than changing the filter, to begin with.

Can Carbon Filters Be Used on the Outside Of A Grow Tent?

Can Carbon Filters Go Outside Of A Grow Tent

Depending on how the airflow for your grow area is set up, carbon filters can usually be mounted inside or outside the grow tent.

Many carbon filter manufacturers recommend specific locations on the instructions.

However, in my experience, it usually doesn’t matter whether or not the filter is directly inside of the grow tent as long as the airflow is set up so that all air passes through the carbon filter.

You need to remember to check if all ducting for the system is 100% secure and that the air can pass through your carbon filter, wherever it may be placed.


If I don’t have a filter, are there other ways to get rid of odors in a grow tent?

Other ways to get rid of the smell associated with grow room or tent is to consider using gels, air purifiers, and odor-neutralizers.
However, all of these options mask odors. Carbon air filters are the most effective option and actually filter out odors.

I Had A Mold Problem In My Home And Bought A Carbon Filter To Fix The Problem, But It’s Not Working?

Carbon filters usually can’t remove mold from the air, even if they’re advertised to. While they’re great at removing odors and many harmful gases from the air, they can’t remove the fine particles found in mold, dust, or pollen. Some filters do an okay job, but it is never 100%.

Why Do I Need A Filter With Activated Carbon?

Activated carbon is carbon that has been treated by hot air, carbon dioxide, and/or steam to make it better at trapping gas molecules. Regular carbon doesn’t have the same amount of “space” available to trap the stuff you want to get rid of and remove it. That means the bad smells might stick around, and you definitely don’t want that!

Is There A Way To Build My Own Carbon Filter?

There are a few ways to build air filters that could help remove bad odors from the air in your grow room or grow tent.
However, the money you save may be offset by the amount of time it takes you to build a filter. Also, you might get worse results! I personally recommend buying one of the filters mentioned above so you get the highest quality crops from your grow tent or grow room. But if you are very handy at making your own things, check out our article on how to make your own DIY carbon filter. It’s an easy 7-step process using materials you can easily get from the store.

I Have installed a New Air Filter, But My Grow Room Still Smells. What Should I Do??

Remember that you need a certain CFM to rid your grow room of unwanted smells. You probably bought an air filter that can’t handle the needs of your room. Calculate the CFM you need by dividing the volume of your room by three. You might also have purchased an air filter with an extremely short lifespan and should consider replacing it with a different brand.

Where to Buy?

Filter Only

EDITOR'S CHOICE for 4x4 Grow Tent
iPower 4 Inch Air Carbon Filter Indoor Plants Grow Tent Odor Control Scrubber with...
Best 6 inch Choice
iPower 6 Inch Air Carbon Filter Indoor Plants Grow Tent Odor Control Scrubber with...
Best 8-inch Choice
TerraBloom Carbon Filter 8" x 24", 46mm Thick Charcoal Bed, Airflow up to 750 CFM. Premium...
iPower 4 Inch Air Carbon Filter Indoor Plants Grow Tent Odor Control Scrubber with...
iPower 6 Inch Air Carbon Filter Indoor Plants Grow Tent Odor Control Scrubber with...
TerraBloom Carbon Filter 8" x 24", 46mm Thick Charcoal Bed, Airflow up to 750 CFM. Premium...
EDITOR'S CHOICE for 4x4 Grow Tent
iPower 4 Inch Air Carbon Filter Indoor Plants Grow Tent Odor Control Scrubber with...
iPower 4 Inch Air Carbon Filter Indoor Plants Grow Tent Odor Control Scrubber with...
Best 6 inch Choice
iPower 6 Inch Air Carbon Filter Indoor Plants Grow Tent Odor Control Scrubber with...
iPower 6 Inch Air Carbon Filter Indoor Plants Grow Tent Odor Control Scrubber with...
Best 8-inch Choice
TerraBloom Carbon Filter 8" x 24", 46mm Thick Charcoal Bed, Airflow up to 750 CFM. Premium...
TerraBloom Carbon Filter 8" x 24", 46mm Thick Charcoal Bed, Airflow up to 750 CFM. Premium...

Should You Buy a Carbon Filter Fan Combo Instead?

Something important to keep in mind when buying an activated carbon filter for your grow room is that you’ll need a fan to direct airflow.

Buying a carbon filter/fan combination might save you money in the long run as it’s a 2 and 1 purchase.

It also can be more convenient for beginner growers who want to try out multiple new products at once that are assured to work together!

I personally recommend a combination package to anyone looking for a combo where every individual piece is made to a high standard. You won’t be disappointed!

VIVOSUN Ventilation Kit 6 Inch 440 CFM Inline Duct Fan with 6" x 18"Carbon Filter Odor...
  • Perfect Combination: This ventilation kit includes a 6-inch 440 CFM inline...
  • Powerful Air Flow Fan: The powerful inline fan with a speed of 2450 RPM can...
  • Excellent Odor Control: The porous activated carbon with 1050+ RC 48...
Choosing the best carbon filter for your grow room


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  • University of California Santa Barbara Science Line. (Eds.). (2011). How many micrograms of VOCs, especially formaldehyde, xylene, and benzene, can a typical air purifier filter? UCSB Science Line.
  • Agranovski IE, Moustafa S, Braddock RD. (2005). Performance of activated carbon-loaded fibrous filters on simultaneous removal of particulate and gaseous pollutants. Environ Technol. Vol. 26(7):757-66. doi: 10.1080/09593332608618516. PMID: 16080331.

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