Inline fans are one of the necessities that all growers must buy when starting to grow cannabis indoors, no matter what the size of your garden is. Whether you have your plants in a specialized grow room, a grow tent, or even a small grow cabinet, you need proper ventilation. Inline fans move the air effectively and efficiently so that the heat in your grow space does not get above what is comfortable for weed plants, about 90 degrees. Increased heat can cause your plants to become dry and wilted, or to absorb more nutrient solution that they regularly would, causing nutrient burn. More heat also means increased relative humidity in most climates, which can create the perfect environment for mold and pests to infest your plants.
Another benefit of good ventilation is the ability to remove odors from your grow op. Most home growers do not like to advertise the fact that they grow cannabis. This is a personal choice and may not always have to do with the legality of marijuana in your state. Cannabis plants have a very strong and very recognizable smell, and although home growers certainly love the finished product, you might not want to smell it all day every day and your neighbors most likely do not want to either. Charcoal or carbon filters offer the most effective means of eliminating this odor. The outbound air from your grow room is passed through a thick filter filled with carbon or activated charcoal, which uses chemical absorption to remove odors from the ventilated air. The molecules carrying the cannabis odor are trapped inside of the pores of the carbon molecules. This is one of the most effective odor filtration methods available and has served weed farmers well for years.
In this article we are going to go over the best carbon filters on the market today. These filters come in different sizes based on the diameter of your inline fan and ducting – From 4″ for small areas to 8″ for more substantial grow rooms. They may all look the same when you shop for filters, but quality differs greatly between brands, so I have picked out the most reliable filters and the best deals.
1. Best Four Inch Filter: VIVOSUN 4 Inch Air Carbon Filter Odor Control with Australia Virgin Charcoal
This four inch filter from VIVOSUN has everything you need and no fluff. It is a simple aluminum framed carbon with an internal carbon pad and a sleek design. The filter flange is removable so that you can replace it without having to buy a new filter. There is mesh on both the inner and outer layers, giving a 53% open are area for better airflow.The charcoal used is a 1050+ Australian virgin charcoal blend for maximum effectiveness. This filter also has a pre-filter to increase efficiency. This filter is an excellent choice for small grow ops with four inch fans. It also comes in six and eight inch sizes.
Price: $29.95 with free shipping
- Machine packed Australian virgin carbon filter
- Internal filter is more effective and looks nicer
- Removable flange
- Aluminium frame is easy to bend
- If bent it will not fit in ducting properly or form an airtight seal
- No warranty
Find more VIVOSUN 4 Inch Air Carbon Filter Odor Control with Australia Virgin Charcoal information and reviews here.
2. Best Six Inch Filter: Think Crucial Carbon Inline Fan Filter & Odor Control
For slightly larger grow ops, you need a larger filter to fit your six inch inline fan and ducting. This filter is designed to last a long time, up to 1.5 years, before needing to be replaced. It has a CFM rating of 400 and is reviewed by customers as durable, reliable and worry-free. This is a professional grade filter that will work great in your home grow op.
Price: $54.99 with free shipping
- Professional design
- CFM rating of 400
- Long lifespan
- No removable/replaceable parts
- No warranty/li>
- Ducting sold separately
3. Best Eight Inch Filter: TerraBloom Premium Carbon Filter
If you have an extra large grow room, you need an extra large ventilation system and a very well made and effective carbon filter.
This TerraBloom filter not only looks great, it is well designed and suitable for use in any professional level grow op. This filter uses top grade RC-48 carbon from Western Australia. The carbon bed in this filter is 46mm thick and machine packed. It has very small granules, so that there is at least 15% more carbon in this filter than in the standard 38mm carbon beds you find in cheaper filters. For a professional grow, you need a high quality filter, and this one definitely fits the bill.
Price: $99.99 with free shipping
- Extra thick carbon bed
- Top grade virgin carbon used
- Sleek design
- No warranty
- Relatively expensive
- No removable or replaceable parts
4. Best Six Inch Combination Deal: VIVOSUN Inline Duct Fan & Carbon Filter With Australia Virgin Charcoal
Sometimes it is more cost effective to purchase your inline fan and your filter as a combo pack. This fan and filter set is a great option for anyone looking for a good deal that is also high quality and reliable. The six inch inline fan provides a fan speed of 2,450 RPM and the filter is made of 1050 + RC 48 Virgin Australian charcoal. The flange is reversible. The carbon filter has both inner and outer mesh for a 53% open air area, giving better ventilation and air flow. This combo pack also comes with mounting brackets for the fan and an instructional pamphlet.
Price: $129.95 with free shipping
- Fan and filter both included
- High quality and inexpensive
- Convenient to purchase both at the same time
- Filter pad is not internal
- No warranty
- DUcting not included
Find more VIVOSUN Inline Duct Fan & Carbon Filter With Australia Virgin Charcoal information and reviews here.
5. Best Eight Inch Combination Deal: iPower Inline Fan, Carbon Filter, Ducting & Clamps Combo
Last but not least, here is a combination package that includes all of the materials needed to set up a heavy duty ventilation system in your grow room. This package deal includes an eight inch fan, carbon filter, and 25 feet of flexible ducting. The filter is made with 1050 + IAV Australian carbon. The 745 CFM fan has a lower than average noise level, made with UL components and high quality materials. The aluminum ducting comes with clamps to attach it to the fan and filter, although you may need to purchase additional clamps depending on the configuration of your grow room and ventilation holes.
Price: $164.31 with free shipping
- All equipment included for convenience
- Quiet running fan
- Virgin Australian carbon filter
- No warranty
- Most expensive option
- May require additional clamps