Mesh to prevent bugs from duct/exhaust

HydroKid239 said:

I got this filter on Amazon. Was like 15-16 bucks. I used flex tape to affix it to my fan. View attachment 5147551View attachment 5147552View attachment 5147553
I know it says “carbon” but it’s total bullshit. This thing isn’t stopping any odors.. it will stop small particles from going through your intake tho.. as it has mine.

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The only issue with something like that is surface area is small, Im rural and a lot of dust in the air at times it will fill that up in no time restricting airflow a lot.

What do you guys think of those inline hepa filters? Looks like an automotive filter but intended for inline fans.

I’m building out a hybrid sealed room and I put a 6” vent in the bottom for when/if I want fresh air. It’s paired with a 6” outtake inline fan with a charcoal filter.

at first I thought I would throw a charcoal filter on the intake fan but they seems less effective then a proper air filter. So I’m contemplating the little conical hepa filter or maybe building a little box and running some a/c filters.

Save the expensive hepa filters for mushroom cultivation, like making a laminar flow hood or something IMO. It takes a workhorse squirrel like fan to pull or push through one.

Regular household furnace filters work great, and have 10x or more the surface area of any other filter you could use. Can get them from 1-4 inch thick with more layers too. They are rated up to blocking almost any thing you wouldn't want in your grow, including mold spores and mycotoxins and beyond, costing a few bucks more for the best kind. Sure a big bulky furnace filter doesn't look as good (coming in many dimensions), and takes up more space... but..

It's all about surface area like stated above. Furnace filters are made for higher flow like you want, and a proper hepa would restrict flow and burn out the furnace motor, just like your inline fan probably would too eventually.

Drop That Sound said:

Save the expensive hepa filters for mushroom cultivation, like making a laminar flow hood or something IMO. It takes a workhorse squirrel like fan to pull or push through one.

Regular household furnace filters work great, and have 10x or more the surface area of any other filter you could use. Can get them from 1-4 inch thick with more layers too. They are rated up to blocking almost any thing you wouldn't want in your grow, including mold spores and mycotoxins and beyond, costing a few bucks more for the best kind. Sure a big bulky furnace filter doesn't look as good (coming in many dimensions), and takes up more space... but..

It's all about surface area like stated above. Furnace filters are made for higher flow like you want, and a proper hepa would restrict flow and burn out the furnace motor, just like your inline fan probably would too eventually.

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Great explanation. Thanks for your input. Building a box to house the furnace filters is going to be my next project.

I build my own boxes for them too, and vents they slot right into in my grow rooms. It could be as easy as just taping a filter to a plastic tote (over a hole in the flat lid), and running a duct to it.

I even tape them directly to cheap box fans, to make air filters for around the house for under $30 each. Works better than $300+ hepa units at the store!

Drop That Sound said:

I build my own boxes for them too, and vents they slot right into in my grow rooms. It could be as easy as just taping a filter to a plastic tote (over a hole in the flat lid), and running a duct to it.

I even tape them directly to cheap box fans, to make air filters for around the house for under $30 each. Works better than $300+ hepa units at the store!

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I’d love to see a picture of a filter for your grow room vent.

Furnace filters are great and cardboard is free.
Grab a tote, cardboard box, foam insulation board or wood and slap it together. Use filters on two or more sides for more filter area in a smaller package.

Drop That Sound said:

I build my own boxes for them too, and vents they slot right into in my grow rooms. It could be as easy as just taping a filter to a plastic tote (over a hole in the flat lid), and running a duct to it.

I even tape them directly to cheap box fans, to make air filters for around the house for under $30 each. Works better than $300+ hepa units at the store!

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Could you show us how you're using/connecting those filters. I could use some visuals. I'm a visual learner. Thanks!

Ya I'll snap some pics 4 you guys tomorrow.

In the mean time:


^ You could make the intake "box" filter almost completely out of the furnace filters and tape, at least 5 of the 6 sides of the box, for maximum surface area. Like, not have to change the filter for a year or more style.. The other main side without a filter would be a square panel (cardboard or what have you) with a hole and flange, to connect your ducting, whatever size it may be. That instead of the box fan for a side, like in the link above. Good for large growrooms, or if you have space.. Simple!


Who says the filter has to stay flat? You can fold them into channels, and make a longer skinnier square tube out of 2 bigger filters bent into L shapes, then taped together. Or even cut the outer cardboard frame away, and wrap the filter mesh material itself around a round duct, with holes or slots cut out in it for air to flow through.

Probably even just straight up bend a large filter into a cylinder like shape, by wrapping it around something round first, and then tape the seam shut. Tape a coffee can lid cap on it, and stuff it into your tent port, for the tent growers here..lol

Metal tape is your friend

I'll play around with some old used filters and see if I can come up with new designs, and show you what I mean about modifying them like that.

They make many different dimensions of furnace filters too, some more rectangular than others. 10x14" for example.

Nobody using pantyhose anymore lol

Mesh fruit bags with drawstrings, Easy, cheap and effective. If it gets soiled, just pitch it and slip a new one on!

bam0813 said:

Nobody using pantyhose anymore lol

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Really, what else do two headed thieves put on their heads when robbing a bank