Hi Brian. Song here from Smart Air. First off, we do NOT recommend cleaning HEPA filters as you may have read in the article, and meanwhile we have been trying to reduce the environmental footprint. My guess is that the filter is still within the lifespan since it was berely used. It could smell sometimes if left unused with no wind passing through, and this article may help get rid of the smell. Hope this helps!

Washable HEPA filters are common with wet/dry shop vacs but although they use hepa filters they are not hepa certified vacuums because they leak.

I suspect that a short term mask relies more on electrostatic charge than a HEPA filter that must last for months. I see references that HEPA filters can use charge but it’s a lesser effect than inertial impaction and interception. But I don’t see any real world data.

Could also be measuring the air pressure. Pulling a higher vacuum means a blocked filter. Very unlikely that they count particles.

Stacking the filters might make too much restriction in the air flow, providing less air flow and perhaps too much load on the motor, so it fails earlier. But yes, people place foam filters or paper towels in front to catch the big particles and hair, hoping to extend the life of the expensive HEPA filter. Or find a PTFE washable HEPA filter and cut to match your machine.

It does make a lot of sense to try to understand how filters are damaged by washing, so that you could find a good washing method, but the goal of this test was just to try an average washing method and it failed spectacularly.

Hi Ole,

Danielle here from Smart Air. We left them to dry for a day before putting it back to the air purifier.

I did what you said and then put it in there wet did I just make a humidifier? Lol