Best Carbon Filter for Grow Room – Reviews and Buyer’s Guide

A carbon filter is an essential piece of equipment if you’re growing cannabis indoors. Even if you’re using odor-free fertilizers and pesticides, flowering cannabis has a distinct odor that can be overwhelming when you’ve got multiple plants growing at the same time.

Not only does the carbon filter help with odor control, but it also keeps the environment in the grow tent clean and free of air-borne pathogens that may infect your plants. It’s important to choose the best carbon filter for your best carbon filter for grow room to manage odor and keep your plants healthy—but which filter is that?

The Best Carbon Filters for Grow Rooms Reviewed

#1. iPower 4-Inch Air Carbon Filter

iPower 4 Inch Air Filter Indoor Plants Grow Tent Odor Control Scrubber with Australia Activated Carbon for Inline Fan, Reversible Flange, Prefilter Included, Silver

This carbon filter is the cream of the crop, using one of the most absorbent carbon types in the world – Australian RC412 activated carbon. By choosing an extremely absorbent activated carbon, you’ll be able to filter out strong odors with less odor leakage.

The carbon layer is 50mm thick so all the air that moves between your grow box and the outside is exposed to a thick absorbent layer that will remove most, if not all, undesirable odors and microbes.

The iPower carbon filter comes with a pre-filter that protects the actual filter and carbon bed. The pre-filter absorbs most of the large particles that would otherwise clog up the filter, and it’s recommended that you replace this every six months. This step will significantly increase the lifespan of your filter, which can last up to one and a half years before needing replacement.

An added advantage for the less-technically minded is that setup and installation of the filter is easy, thanks to a plug-and-play system that removes the mess and hassle from the installation process.




  • High-quality Australian RC412 activated carbon
  • Pre-filter extends lifespan
  • Easy installation and setup
  • Affordable
  • Have to replace the entire unit when charcoal wears out
  • Noisy fans

#2. VIVOSUN 4-Inch Air Carbon Filter

VIVOSUN 4 Inch Air Carbon Filter Odor Control with Australia Virgin Charcoal for Inline Fan, Grow Tent Odor Scrubber, Pre-Filter Included, Reversible Flange 4' x 14'

The primary claim of this filter is that it provides 100-percent filtered airflow, meaning there are no pockets of air that escape coming in contact with the activated carbon filter. The carbon itself is pure Australian activated carbon that will last for multiple years, according to the manufacturer.

This filter is versatile for many different applications thanks to a reversible flange and base. It can be used as an intake or exhaust filter and with varying fans types for different applications.

The unit does come with a pre-filter that removes most large particulates before they enter the unit itself, protecting it and extending its lifespan. If you want to keep your carbon filter working for as long as possible, you do need to pay attention and replace this pre-filter when necessary, about once every growth cycle.

Several users have also reported that the activated charcoal doesn’t last for very long and odor elimination fails after about six months, so keep that in mind when buying this filter that you may end up replacing it after each growth cycle. It may be more affordable in the long run to obtain a higher quality filter.




  • Vivosun’s customer service department is responsive
  • Reversible flange and base mean you can use the filter for various applications
  • Easy to install
  • Several users report poor construction issues
  • Short lifespan

#3. GROWNEER 4-Inch Air Carbon Filter with Reversible Flange

4 Inch Air Carbon Filter with Reversible Flange Odor Control Activated Charcoal Filter Pre-Filter Included Air Scrubber for Grow Tent Indoor Plants

Like many other filters discussed in these reviews, the GROWNEER uses 1050+ IAV Australian charcoal to absorb odors, which has a high absorbency to absorb even the most pungent of smells. The fan that comes with the filter is excellent at controlling heat, which means that the temperature in your grow room won’t be affected by the presence of the filter.

It has a reversible flange and base, which means it can be used either as an intake or exhaust filter. Another application of this reversible feature is to flip the carbon filter over, thereby extending the service life of the filter.

The package comes with the filter, one belt, and one pre-filter that needs to be maintained to prolong the service life of the filter itself. The expected service life of the filter is about one year, depending on how much stuff the carbon has to absorb. Obviously, with heavier usage, the service life will go down.




  • Has a controller to regulate the fan speed
  • High-quality carbon removes up to 90 percent of strong odors
  • The fan is very loud at default settings
  • Challenging to assemble compared to other filters

#4. Phresh Carbon Filter 701005

Phresh Filter 701005 Filter, 6 in x 16 in | 400 CFM

Undoubtedly the king of the pack, the Phresh carbon filter offers several features that other carbon filters don’t and is well worth it despite the cost.

The Phresh filter uses RC-48 activated carbon, which is machine-packed into the 1.8-inch filter bed. Machine packing allows for more carbon to be packed into the same space, lessening the movement of carbon in the filter bed and upping the number of odors that can be removed.

The filter has aluminum tops and bases that make it the lightest filter we’ve reviewed, perfect for smaller grow room that might not be able to handle the weight of heavier filters. The cone-shaped design ensures that air flows through the filter freely and that, combined with the anti-air bypass system means that a maximum amount of air is passed over the carbon filter.

Like the other filters we’ve reviewed, the Phresh filter comes with a pre-filter that is essential to extending the lifespan of the unit when appropriately maintained. Phresh claims that their product can last up to two years when correctly maintained, justifying the higher price point.




  • Long lifespan
  • Aluminum construction makes for a lighter filter
  • Reputable company with an excellent track record of producing high-quality filters
  • Expensive
  • The fan can be loud if not dampened

#5. TerraBloom Activated Charcoal Air Carbon Filter

TerraBloom Air Carbon Filter, 4' x 12', Activated Charcoal Scrubber for Inline Duct Fans Up to 200 CFM. for Grow Tent Ventilation Kits, Hydroponics, Odor Removal

The TerraBloom filter uses top-grade RC-48 charcoal from Australia packed into a 1.8-inch filter bed, resulting in more carbon and more effective air filtration. As there is more carbon in the filter bed, it also means that the unit has a longer lifespan that filters that have a thinner filter bed. I fact, the expected lifespan for this unit is two years of continuous usage.

The entire unit comes pre-assembled, with both the flange and aluminum base assembled, allowing for quick and easy installation. The aluminum base means that the filter is lighter than other units at a similar price range. Unfortunately, since the flange comes pre-installed, you can’t reverse it when it starts failing to extend its lifespan.

Overall, the TerraBloom is a close competitor to the Phresh filter, with the same quality carbon on a thick filter bed, same lightweight aluminum construction and same expected lifespan for a more affordable price.




  • Slightly cheaper than the Phresh filter
  • Lightweight construction
  • High-quality carbon filter
  • Thicker filter bed means a longer lifespan
  • It’s a big filter
  • Non-reversible flange and base

How to Choose a Top Carbon Filter For Grow Room

While you can get away without having a carbon filter in your grow room or tent, a carbon filter is incredibly useful in filtering out odors and also preventing harmful microbes from entering and infecting your plants.

There are plenty of cheap options on the market, but it’s better to find a filter that offers high performance for a longer time. You will quickly find that most cheap filters stop working within months if they ever worked effectively at all.

When looking for a filter, there are a couple of things that you should look or. If the filter you’re looking at meets these criteria, chances are you’ll be happy with the product you’ve bought.

  • Amount of carbon: The more activated carbon in the filter, the more effective it is, and the longer it will last. The thicker the filter bed, the more carbon the filter will have. Look for filter beds that are 1.8 inches (46mm). They will offer the best bang for your buck.
  • Pre-filter: A pre-filter is a barrier between the carbon layer and the outside air. It’s designed to remove larger particles that would otherwise clog up your carbon filter and ductwork. Many are removable and machine-washable, and it’s a good idea to maintain these properly.
  • Materials and durability: When looking for a carbon filter, try to find one that uses aluminum for its base and flanges. Aluminum is not only lighter; it’s also more durable, which means it can stand up to repeated usage. Some filters are made with incredibly flimsy materials, and they don’t tend to last very long, making them a waste of money.
  • Cost: Obviously, you need to work within a budget, but when it comes to filters, you get what you pay for. There are no secret, excellent cheap options, so go for the highest-quality option you can find for your budget.

In Conclusion – Carbon Filter

Your best carbon filter for grow room needs a filter to stop odors from escaping and also to keep bugs out of the system. A carbon filter is an excellent choice since it’s reliable and relatively quiet. Carbon filters are only as effective as the carbon in them, so when choosing a filter, go for one that has high-quality activated charcoal and has plenty of it. Thicker carbon filter beds mean a longer lifespan and more effective odor control and filtration.