HEPA filtration is the number one defense against molds and fungal issues with cannabis. Harvest molding while it dries? Trimmed flowers molding in your jars? Packed a bunch of cannabis away, and come back to find it's ruined with mold? In a well ventilated flowering room (3 complete exchanges of air per minute), over the 2-3 month cycle, the trichomes of your plants can pick up an amazing number of mold spores.
When moisture levels and temperatures levels are high enough, those mold spores will cause enough mold to ruin a harvest in only a few days.
HEPA filtration stops fungal spores, stray pollen, bear and beaver dander, feces dust from all kinds of animals, pet hair, human hair, carpet and clothing fibers, bugs and more.Once you've smoked HEPA grown cannabis for a while, everything else starts feeling harsh in comparison.
HEPA filters are so cheap to build, everyone with DIY skills should be using them. I recently built one for the LED cab I'm building, and figured everyone here could benefit from a separate thread.
Here's the completed filter, attached to a fan.
The 'Plenum' before installing the filter. This can be as simple as 1x4 and thin plywood, screwed together and sealed with caulking. With larger sized filters, you'll want to cut multiple square holes, leaving cross braces. This filter size '14x20' will filter up to an 8" fan, and a 25x25 filter will work for 10-12" fans.
Drywall channel for corners is used to create a frame for the filter. The frame is secured and sealed to the plenum, and the filter is taped into the frame. When the filter needs to be replaced, simply cut the tape and exchange dirty with new, then re-tape.
The drywall corner channeling cut, bent and sealed to the plenum.
Closeup of a cut, secured and sealed corner.
The HEPA filters I typically use.
Filter installed to plenum, and is now all taped up and ready to go.
Hope a great many of you try this and enjoy it. I've been doing it for 15+ years and love the difference. Be good to yourselves.