A carbon filter is vital to any grow room. They are designed to remove strong odors and harmful gases from the grow room.
Choosing the right size for your grow space is SO important, and this guide will teach you how to pick the best carbon filter for your Grow Room Or Grow Tent.
But what are carbon filters?
Carbon filters are filters made of activated charcoal intended to remove strong odors and harmful gases from the air.
In indoor grow rooms, they’re 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-neutralisers may help keep bad smells from smelling, but they just 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.
What will a carbon filter do in my grow room?
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 improving 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!
What To Look For In A Carbon Filter
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:
- The area covered
- The quality of carbon
- How long the filter lasts
- What it comes with
- Are they portable
First of all, you want a carbon filter that can cover the area of your grow room or tent 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 cost is usually offset by the increased lifespan of the filter.
Cheaply made (and cheaply sold) options sometimes only last a couple 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.
The more carbon they use =, the more effective they will filter the air.
You also need to consider 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 usually. Some fabric sleeves and filters are even machines 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 and inline extraction fan for my grow tent or grow room?
As discussed, choosing the right size carbon filter to cover the overall space of your grow room is the most important deciding factor.
You NEED to get a filter that will match the area of your groom room.
In order to buy the correct carbon filter, you’ll need to calculate the volume of the grow tent or grow room. You can do that by using this formula below:
VOLUME = LENGTH x WIDTH x HEIGHT
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.
4 Of the Best Carbon Filter For Grow Room and grow tent
IPower Air Carbon Filter Odor Control Scrubber
Phresh Filter 6 In X 24 In, 550 CFM
TerraBloom Premium Carbon Filter
8 X 16 Inch
Phresh Intake Filter 10 In X 16
best 4 Inch carbon filters
4” carbon filters are the smallest option out of all the carbon filters available, but you still have plenty of options to choose from.
IPower 4 Inch Air Carbon Filter Odor Control Scrubber
Why? Because it is designed to maximize airflow.
It is also very easy to install, is well-made, and has been extremely durable to date.
I used it for six months before needing to replace any filters!
However, I have heard from other buyers that their carbon filter came in in bad shape.
Having to do a return and then buy again is NOT conducive to reducing the odor in your grow room or tent.
So, overall, it works great as long as it comes in looking great. If not, you’ll have to return it and try again!
Phat Filter 12 Inch X 4 Inch, 200 CFM
The Phat Filter is a professional grade filter and works extremely well on small grow tent or grow room.
If you want a high-quality filter for a small room, this is the best option.
It is made from the oldest charcoal on Earth, and its performance is truly impressive. It removes odors even better than the iPower filter.
Yet, I wouldn’t recommend this filter to beginners in setting up grow tents who expect to experience difficulties.
The support community is much smaller than with the iPower option. You’ll have more people to ask for help (if you need it) by buying the iPower.
However, if you DO set it up right, I think it works wonderfully!
Best 6 inch carbon filters
6” carbon filters are the next size up when it comes to purchasing carbon filters for your grow room or grow tent.
Typically, these filters cover spaces that need about 400CFM to control odors.Some of my favorite options for 6” carbon filters are listed below
iPower 6 Inch Air Carbon Filter
Similar to the 4-inch option, I love the 6-inch carbon filter by iPower because it does its job well and it lasts a long time compared to some alternative brands.
It might do its job so well because of the charcoal used.
Australian activated charcoal is INCREDIBLY absorbent.
There is virtually no smell left behind incorrectly sized rooms after filter installation.
Phresh Filter 6 in x 24 in, 550 CFM
Similar to the iPower 6” carbon filter, the Phresh Filter 6” carbon filter knows how to perform.
It quickly removed any smells from my grow room.
The only real improvement, however, was an important one.
This filter is designed for a longer lifespan and can last up to TWO YEARS.
Plus, it is so much lighter in weight than other brands and the charcoal used in this filter has no chemical additives.
Overall, this is my favorite option for 6” carbon filters.
CoolGrows 6 inch Air Carbon Filter, Odor Control Grow Tent Kit
The CoolGrows 6” filter is a no regret purchase. Like the other 6 inch options I’ve reviewed, it works super well!
It is completely capable of removing smells from correctly sized grow rooms.
And, for $10 less than the iPower filter, it’s definitely worth the buy.
However, the lifespan is even shorter than the 6” iPower filter. It lasted me less than 3 months of usage.
For a cheap filter, it works well. The lifespan is the only drawback.
Best 8 inch carbon filters
8” filters typically cover a little bit of a larger area than their 6” alternatives.
Remember to look at the individual CFMs, however, because there is sometimes some overlap.
My favorite 8” options are below.
TerraBloom Premium Carbon Filter 8" x 16"
To be perfectly honest, this was the first TerraBloom filter I purchased. After its excellent performance, it won’t be the last.
It is a long-lasting carbon filter that uses some of the best carbon in the world to filter bad odors out of the air completely.
The reason why it performs so well is that the TerraBloom uses small granulated carbon bits instead of pellets or chunks of carbon.
Another plus is that it includes two machine washable fabric sleeves that saved me time and money!
I recommend this product to both beginners and experienced grow room growers. I think this product is the best 8” option and the best at covering areas that need around 600 CFM.
iPower 8 Inch Air Carbon Filter with Virgin Charcoal for Inline Fan
Yet another iPower air filter - you’d think I’m in love and I am! They’re honestly just a great, long-lasting, effective line of carbon air filters and switching from one to the next is incredibly easy if you’re increasing the size of your grow room or grow tent.
Like the other fans, the 8” filter was able to completely rid my grow room of any smells!
My only advice when it comes to the 8” choice is to keep in mind that, as the size of the fan grows, so does the amount of noise it makes. This filter is louder than the 4” and 6” filters.
10” carbon filters
10” filters cover a larger grow room than the 8” alternative. Many of these filters on the market run at around 1000 CFM.
Phresh Intake Filter 10 in x 16
Like the 6” carbon filter by Phresh, this 10” option is designed with quality in mind.
It maintains 90% of airflow, is 100% recyclable, and completely removes any odors from appropriately sized rooms.
While it may be a little bit pricey, this carbon filter is worth the money. Similar to the 6” option, it can last up to 2 years, works well, and is lightweight - which makes it worth the added cost.
Hydrogarden Mountain Air 10-inch
Another long-lasting option, the MountainAir Carbon Filter completely removes any unwanted odors from larger grow rooms.
However, unlike other large carbon filters, it includes noise-reducing technology.
This comes in handy when trying to run a quiet grow room!
Additionally, it comes with a machine washable fabric sleeve that makes this product affordable, efficient, and, all in all, an excellent choice for any large grow tent like 10x10!
Best carbon filter fan combo to buy in 2019
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.
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!
Some great combination options for filters between 4” and 8” are listed below:
Ipower 4 inch inline fan carbon filter 8 feet ducting combo
Vivosun 6 inch inline duct fan with 6" x 18" carbon filter
Ipower 8 inch 750 cfm inline fan carbon filter combo
8 X 16 Inch
iPower 4 Inch Inline Fan Carbon Filter 8 Feet Ducting Combo
A great combination option for if you have a 4x4 grow tent setup, the iPower 4” filter and fan pack are one of the highest reviewed combo purchases.
One of the reasons I highly recommend it is that all of the pieces are designed to work with each other quietly, and can be set to varying levels of speed quite easily.
Additionally, this system is designed to remove unwanted heat at the same time it reduces any odors in the grow tent!
VIVOSUN 6 Inch Inline Duct Fan with 6" x 18" Carbon Filter
The VIVOSUN combination pack is another great example of why you should consider purchasing your filter and your fan at the same time.
These two sold together work perfectly!
In fact, even when you connect 2 seperate tents and run this fan/filter to clear the air, absolutely no odor can be detected from outside the grow room!
iPower 8 Inch 750 CFM Inline Fan Carbon Filter Combo
Let’s cut to the chase: all of the iPower carbon filter products are simply amazing. They remove odors without a problem and last a decent amount of time.
This is yet another example of a great product.
All of the pieces are made to be high quality, and a special emphasis is put on reducing the noise typically associated with 8” filters.
I personally recommend this combination package to anyone looking for a combo where every individual piece is made to a high standard. You won’t be disappointed!
What are the other ways to get rid of odor in a grow room?
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 this options simply mask odors.
Carbon air filters are the most effective option and actually filter out odors.
How to take care of your carbon filter
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 smell of the room.
However, in order for the air filter to work properly, even if correctly maintained, you have to 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.
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 for you 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!
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 of 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 just 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.
Tips & tricks
- 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.
- Remember, 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 by width by 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 filter.
Q & A
Q: I had a mold problem in my home and bought a carbon filter to fix the problem! It’s not working! What do I do?
A: 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 just can’t remove the fine particles found in mold, dust, or pollen. Some filters do an okay job, but it is never 100%.
Q: I don’t understand the difference between regular carbon and activated carbon! Why do I need a filter with activated carbon?
A: 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!
Q: All of these options seem expensive! Is there a way to build my own carbon filter?
A: 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, but 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.
Q: I bought an air filter, but my grow room still smells. What should I do??
A: 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 3.
You might also have purchased an air filter with an extremely short lifespan and should consider replacing it for a different brand.
Lindsey Hyland grew up in Arizona where she attended University of Arizona’s Controlled Environment Agriculture. She has supplemented her formal education by working on various organic farms, including spending a semester abroad in India.
Growing and/or raising just about anything gets her excited. She is especially passionate about environmental justice and low-tech, sustainable ways to better run small-scale farms and homesteads. Lindsey started Urban Organic Yield to discuss gardening tips and tactics.