My intakes are all 4" circles (2 per each room), and I’d like to put HEPA filters on each intake. Does anyone know where I can get relatively cheap HEPA filters that are around this size or big enough to cut into pieces this size? These filters seem to be very expensive here in Canada.
Any links or info would be appreciated!
Im following. Although, im in the states…
thats a good idea I need some kind if filter aswell… whether its cat hair or pollen, im playing a risky game lol
Ya a friend suggested them I can’t believe I never thought of it before. If you could seal a room perfectly and have air only go in through the HEPAs you should never have any issues with mould or mildew. They get anything larger than .3 micrometers.
I did find these… they are bigger than 4 inches but I think could be adapted. Bonus feature of a carbon pre-filter too
Ya i saw those, they look ok but over $100 to do all my rooms and who knows how long they last?
Hmmmm I see. Is it possible to build an air cab that uses furnace filters and tie them all into the cab? The price seems to be the same regardless of which option you’ll choose, but the furnace one may give you longer usage between changing
For material to DIY/chop up, check out vacuum cleaner bags & home HVAC filters. 
Try looking at shop vac hepa filters, easy to adapt to ducting and you just gotta slap a cover over the other end.
I ran a room once where the intakes came in through shopvac HEPA’s with a plastic tub lid glued over the side I needed to close on the filter. Worked great.
I think that’s what I’ll do. Could maybe be attached with a duct cap (with some holes) and a screw, with a rubber washer to seal the end… will have to report back.
Maybe look at auto supply stored for professional painters , the filters they use are good and decent price…
These guys are awesome and will last for years.
Thanks all, I’ll look at vacuum and furnace HEPA filters they’ll be bigger for sure.
@almostdone we have a tub shroom for the tub drain that works well, I didn’t know there was a whole line of shroom products lol. Sadly at $90 a piece I’d have to drop like $500 to do all my rooms. Tempting but too costly for me!
there are different levels of hepa, so the least expensive do the least as a general rule
Those shits cost like $130 each at my local grow store ! Gotta be some kind rich baller to be able drop that much on intake filtration
for best price i got can filters hepa at amazon, cant find them,that was 2 yrs ago
but did find this
Not rich nor baller…lol. The 4” can be found online for 60ish a piece. I purchased four of the 8” almost ten years back for 86 each. After factoring in the cost of reoccurring replacements of other options and the volume of waste going to the landfill the dust shrooms were the least expensive option over time.
HEPA is a standard where the filter has to trap something like 99.5% of particles greater than 0.3 microns. If it doesn’t do that its not legally allowed to be called HEPA. Now whether or not there’s any testing or enforcement of the standard is questionable…
Those square filters look great!
I’d like to find the source for that HEPA foam, it would be perfect for making custom filters. Also I’ll make them and sell them for $40 haha
Right and they have merv ratings the higher the rating the more thye cost