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Link? I'm interested. However, I suspect availability plays into it. Almost anyone can pick up a couple of rectangular HEPA filters and a box fan from the lo

by bsder 4y ago

Link? I'm interested. However, I suspect availability plays into it. Almost anyone can pick up a couple of rectangular HEPA filters and a box fan from the local hardware or big box store. I've never seen a cylidrical HEPA filter. So, I probably need to order that from an industrial supplier. And, aren't duct fans kind of noisy? Do they make quiet ones? In addition, this fan/filter seems even easier: https://smartairfilters.com/en/blog/cannon/ https://smartairfilters.com/en/blog/cannon/

joshvm 4y ago
The duct fan + filter combo is how lots of cylindrical consumer units work (e.g. Levoit, Philips, etc). They just use crappy fans which don't really pull any air through, or they're very expensive for what they are. In terms of availability, I think the current popularity helped, otherwise you could also look at the auto market, lots of cylindrical filters there and they'd be fine for pulling out stuff like pollen, though you might want a carbon filter as well. I have no idea what's required for HEPA certification, but lots claim to be: https://www.amazon.com/LEVOIT-Core-Replacement-High-Efficiency-300-RF/dp/B07RSZSYNC https://www.amazon.com/LEVOIT-Core-Replacement-High-Efficien... It has an outer dust mesh, the HEPA filter and a carbon insert. They're all the same though, I think you could use any manufacturer's filter. Longevity isn't really an issue if a supplier goes bust, just re-make the adapter ring. Pretty much all you need and you don't need to worry about sealing the corners. According to OP's link, they use a duct fan booster which is a lot quieter than a box fan (at least the claim is it can go down to 16 dB). Though a question is does a can-shape system work better? Or would you get the same effect if you used a single flat filter with the same "unrolled" area? I have no idea, and there's so much uncertainty involved with DIY testing.
jrochkind1 4y ago
Hm, I feel like cylindrical HEPA filters are common for shop vacs and widely available? Searching "HEPA filter shop vac" on home depot gets what looks like plenty; or are these not what would work for that kind of design, maybe we're talking about different things? They are "cylindrical" by being pleated.

by bsder 4y ago

joshvm 4y ago

The duct fan + filter combo is how lots of cylindrical consumer units work (e.g. Levoit, Philips, etc). They just use crappy fans which don't really pull any air through, or they're very expensive for what they are. In terms of availability, I think the current popularity helped, otherwise you could also look at the auto market, lots of cylindrical filters there and they'd be fine for pulling out stuff like pollen, though you might want a carbon filter as well. I have no idea what's required for HEPA certification, but lots claim to be: https://www.amazon.com/LEVOIT-Core-Replacement-High-Efficiency-300-RF/dp/B07RSZSYNC https://www.amazon.com/LEVOIT-Core-Replacement-High-Efficien... It has an outer dust mesh, the HEPA filter and a carbon insert. They're all the same though, I think you could use any manufacturer's filter. Longevity isn't really an issue if a supplier goes bust, just re-make the adapter ring. Pretty much all you need and you don't need to worry about sealing the corners. According to OP's link, they use a duct fan booster which is a lot quieter than a box fan (at least the claim is it can go down to 16 dB). Though a question is does a can-shape system work better? Or would you get the same effect if you used a single flat filter with the same "unrolled" area? I have no idea, and there's so much uncertainty involved with DIY testing.

jrochkind1 4y ago

Hm, I feel like cylindrical HEPA filters are common for shop vacs and widely available? Searching "HEPA filter shop vac" on home depot gets what looks like plenty; or are these not what would work for that kind of design, maybe we're talking about different things? They are "cylindrical" by being pleated.