DIY silent air filter for pollen, dust mites, other allergens and dust

If you own glossy black equipment, you’re probably aware that even after a mere day of not dusting, a thin layer of dust has accumulated on top of your appliance. According to, this domestic dust mainly comes from cloth (fibers), pollen and dead skin cells, although they don’t cite a source for that claim.

If you’re part of the 55% of the population that claims has allergies (source) you probably also know that many allergens circulate in the air around us, causing discomfort and millions of dollars in lost productivity.

So what to do about it? Well, we could filter it out using a commercial air purifier, but those aren’t really quiet enough for day- and night use in a home. This quote is taken from a review of the $70 Hamilton Air Cleaner that comes up as a top result on Amazon:

And it isn’t silent on the lowest setting, unlike some reviewers said. The noise is similar to a fan on low speed or a refrigerator.

So obviously we have to make one ourselves. Here it is:

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It’s one of the top fans from combined with a vacuum cleaner filter, attached with a zip-tie around the fan, with a 6V phone charger as power supply.  The filter has gotten pretty grey from all the dust that the filter has caught in just under 2 months. Cost is $9.99 for a new fan of this sort plus $0.50 for the filter and $5 for the adaptor, so you could make several of these for the price of one commercial unit. It’s also dead silent from more than 30 centimeters away.

The air flow of this Nexus fan at 5 volt is, according to Silent PC review here, 13 cubic feet per minute, or 22 cubic meter per hour. A room of 5*5*2.5 = 62.5 cubic meter should be completely filtered multiple times over in 24 hours: 1/3 of the air gets filtered in 1 hour, so in 6 hours only 0.66^6 * 100% = 8% of the dust is left over, and after 10 hours 1%. This is of course assuming that the fan randomly samples air from the room, and doesn’t only recirculate the air around it. The smallest particles that the filter catches are, according to the label, 0,3 micrometers. That should provide adequate filtering according to this graph, courtesy of

Now what to do about the aesthetics of this device? It doesn’t look like something you would want in your bedroom, but an enclosure would function as a sounboard and would amplify the noise.


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2 Responses to DIY silent air filter for pollen, dust mites, other allergens and dust

  1. geoff wise says:

    Don’t know where you can get this fan for $5 and the charger for $1. More like $10 for the fan and $7 for the charger.

    • You’re right, and I changed that part now. But ATM I can’t even find the spcr recommended fans (scythe, nexus, noiseblocker) on the US market (newegg, microcenter) so the $10 is still a shot in the dark.

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