MountainAir Carbon Filters – 4" to 12" (All 10 Sizes) | Grow Tent Odour Control

The cheapest carbon filter is rarely the cheap one. A budget filter that gives up after a year and a premium one that lasts three cost about the same per month. The difference is that one of them makes you do the job twice, usually just when the smell has already escaped. MountainAir is the second kind. It's the filter people buy once, then forget they own.

Forgetting is the point. A carbon filter does its best work when nobody, including you, notices anything at all: no odour drifting out of the tent, no neighbour asking what you're cooking, no drone from a fan straining against a clogged filter. MountainAir is built around exactly that sort of invisibility.

This listing carries all 10 MountainAir sizes sold in the UK, from 4" to 12", including a short and a long body in 6", 8", 10" and 12". Pick your size from the drop-down; the model code, neck × body size and maximum airflow are in every option name, so you can match it to your fan at a glance.

Why growers choose MountainAir

• Low-resistance carbon. MountainAir uses an activated carbon that is very low in density but high in mechanical strength. Air moves through it easily, so your fan isn't fighting the filter. The maker quotes airflow resistance of under 10%, which means more real airflow and less noise.
• Built to last. MountainAir rates its filters at two to three years of service in normal use, well beyond the typical budget filter.
• Spare pre-filter sleeve included. Dust is what kills carbon filters early, because it clogs the pores before odour ever reaches them. The sleeve catches it first. Wash one while the other is on duty.
• More value as you size up. Bigger MountainAir filters work out cheaper per cubic metre of air cleaned, so a larger filter often pays for itself.

Which one is yours?

Not just for growers

A carbon filter does one simple job: it takes smell out of moving air. That's useful in more places than you'd expect:

• Grow tents for herbs, chillies, tomatoes and flowering houseplants
• Mushroom fruiting chambers, which give off a surprisingly earthy aroma
• Drying rooms for herbs, chillies and flowers
• Fermentation and home-brew corners
• Hobby rooms with paint, glue or resin smells (for odour only; a carbon filter is no substitute for proper fume extraction or a respirator)

Rose's Pro-Tip

"If one size comes in two lengths, buy the longer one. More carbon means the same airflow is spread across a bigger bed, so the air moves through more slowly, gets scrubbed more thoroughly and the filter lasts longer. It's the rare upgrade that saves money. And always pull air through the filter rather than pushing it: mount it inside the tent with the fan drawing through it, so any leak is air coming in, not smell going out. Keep humidity under about 80% too, because damp carbon stops working."

How to match a filter to your fan

Start with the duct diameter. It's simplest when fan, filter and ducting all share one size. If they differ, go for a filter slightly bigger than the fan, never smaller. Ducting and the filter both add resistance, so your fan will move less air in real life than its free-flow rating suggests. Pick a filter rated about 20% above your fan's free-flow figure, and it will work better and last longer because it never has to run flat out.

What's in the box

• 1 × MountainAir activated carbon filter in the size you choose
• 1 × spare pre-filter sleeve

Ducting, clips and the inline fan are sold separately.

Quick set-up tips

• Match the neck size to your fan and ducting (4", 5", 6", 8", 10" or 12"). If in doubt, go one size up on the filter, never down.
• Fit the filter inside the tent or room with the fan on the clean-air side, so the fan pulls air through it.
• Hang it on chains or sit it on a stand. Don't let the filter's weight hang off the ducting.
• Keep the sleeve on. Wash or replace it when it looks dusty, and keep humidity below about 80%.

Specifications

Every MountainAir filter comes with a spare pre-filter sleeve. Weights are for the filter itself; the packed parcel is a little heavier.

FAQ

How long will it last?
MountainAir rates its filters at two to three years in normal use. Real life depends on how hard the filter works, how humid the air is and how much dust gets in. Keep the sleeve clean, keep humidity under about 80% and stay within the rated airflow, and you'll get the most from it.

Does it need a fan?
Yes. A carbon filter is passive, so it needs an inline fan of the same (or slightly smaller) duct size to pull air through it.

Can I mount it horizontally?
Yes. Carbon filters can hang vertically or lie horizontally. The 1 metre versions weigh 18–31kg, so support them with a filter stand or ceiling chains, never the ducting.

Why is the longer body better than the shorter one in the same size?
The longer body holds far more carbon, so it can clean a lot more air and still keep it in contact with the carbon long enough to catch the odour.

Which size do I need?
Start with your fan's duct size, then choose the filter whose maximum airflow is about 20% above the fan's free-flow rating. The table above shows the airflow for every size.

Is the spare sleeve really included?
Yes. Every MountainAir filter ships with a spare pre-filter sleeve, so you can wash one while the other is on duty.

Shipped from Coventry by tracked UK courier | Genuine MountainAir product | Friendly UK support from Black Flag Horticulture