4 inch best carbon filters compared

Introduction to the top carbon filter for grow rooms


Although there has been a lot of progress in various national laws around the world those past few years, our plants are still considered illegal in many places, exposing us to potential legal problems.

As much as we all love the sweet smell of our crops and enjoy noticing its impressive increase during the final stages of our culture, it can become a serious issue for most of us.

That’s why carbon filters for grow rooms are so handy! The activated carbon they contain will absorb anything from the exhausted air, helping you gain grow room odor control and keeping you safe from nosy neighbors and law enforcement agents.

On top of that, a grow tent with the best carbon filter eliminates any airborne pathogens potentially harmful to your plants.

filter and fan grow tent setup

photo source: servovendi.com


Most new growers underestimate the smell’s power and will rush to buy filters in a hurry when confronted with its pervasive presence. In order to avoid this situation and before choosing the best carbon filter you should consider:

  • Your fans CFM (Cubic Feet per Minute), it’s the most frequent rating you’ll find on your fan and represents the air volume it can suck out during a minute. Your filter rating must always exceed it (ideally by 20 to 30%) to ensure a good exhaustion.
  • Vacuuming the filter before first use to remove carbon particles, as they can be very hard to remove. You can even do it outside for more security.
  • Being careful if using a cheap inline fan and carbon filter. Inline fans like the one in your bathroom are often not powerful enough for carbon filters, resulting in a short lifespan.

So remember a good filter is useless without a proper exhaustion.

Best Rated carbon filter Comparison Table

Carbon filters review


Power GLFILT4M Air Carbon Filter and Odor Control – 4-Inch

price $

  • 1050+ IAV Australia charcoal
  • Reversible flange
  • Pre-filter included
  • Odor control for better privacy
  • Cleaner air to promote better health


This is our top pick! We highly recommended it as it offers the best balance between price and efficiency. Its Australian virgin charcoal will provide an odorless air exhaustion for several sessions.

It features a pre-filter to prevent excessive dust from clogging the inside and detailed instructions to open the can and reverse the filter, increasing its lifespan.


Phresh 701003 Carbon Air Filter, 4 by 12-Inch, 200 CFM

price $$

  • 46mm (18″) RC-48 activated, certified virgin carbon bed
  • Flange & pre-filter included
  • Unique “Anti Air Bypass” System
  • Sealed, bagged, boxed and labeled directly after manufacture for optimum life span     
  • handling and presentation
  • Large selection of sizes available to fit any application


This Phresh carbon filter is a high-end product. With a reported service life exceeding two years, it’s among the most performant models on the market. Slightly longer than the previous one, it is sturdy built with good quality materials and thus relatively light-weighted.

It’s a really good item but its cost is higher. We recommend it for those with a bigger budget!



Phresh 701200 Duct Silencer, 4-Inch by 12-Inch

price $

  • Sound reducing acoustic foam decreases fan noise by up to 50%
  • Use with fans in conjunction with carbon filters, light systems and more
  • Attach a Phresh Silencer to the intake or exhaust side of a fan; Use on both sides for maximum sound reduction
  • Durable and light weight aluminum body; Compact size is easy to install




Phresh 701005 Carbon Air Filter

price $$

What we love:

  • It’s long lasting – up to 2 years
  • It is available in many sizes
  • It’s very light
  • It’s easy to install

What needs improvement:

  • Pricebutton

– Read full review of this filters here – 

Phresh Filters are the lightest available. It is all thanks to aluminum top and bottom. Aluminum is light, so it significantly allows to reduce the weight of the whole product. The company also came up with a way to place inside the RC-48 Australian activated carbon that makes the filter more efficient and light. This special carbon is very absorbent thanks to its porous surface. Manufacturer, for best results, also used the purest form of charcoal called “activated virgin” carbon. Such construction allows the filter to absorb up to 108,3% of its own weight. On top of that, the unit keeps 99,9% of bugs, moulds, pollen and dust away

Although Phresh 70100 and other filters of this company are one of the more expensive, they do have a long lifespan. When used according to manufacturer guidance the product can last up to 2 years. Such long span is partially due to high-quality pre-filter fitted within the unit.


Worth the investment, this duct silencer will match any 4’’ ducting, reducing noise nuisance a fair bit. It’s very light and comes highly recommended for those of you with smaller structure grow tents who wish to have a noiseless environment.