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Re: Best Air Cleaner for Large Dust

A Reader writes:

Hello.

I have no dust allergies or other health problems.

I'm just trying to reduce the amount of dust in my office which accumulates itself to my computers and another one to reduce dust in my very large closet.

I'm confused about what type of machine I need. I want to purchase something quality and will pay for it, but I don't want to spend more than necessary for a product that provides benefits that I don't necessarily need.

Any help or direction would be appreciated.

A Reader.

Ed's Reply

Hey Reader;

Air purifiers are designed to capture very small particles. The visible dust you want removed is hundreds of times as big as the .3 micron HEPA specification size.

To remove fine particles, the HEPA filter must operate at a high static pressure, which slows throughput. This is why a $900 IQAir has throughput similar to $250 air cleaners.

HEPA filters are a poor choice as coarse dust collectors.

So what you need has more in common with dust collectors sold for woodworking shops than with room air purifiers marketed for health purposes.

Look at the lint screen on your clothes dryer - what you need is considered only a "prefilter" on an air purifier.

To collect 18-50 micron visible dust, I modify inexpensive HEPA-type air cleaners by removing the phony "HEPA" filter, with its airflow restriction, and substitute multiple layers of polyester mesh and a piece of fiberglass window screen.

This makes the former air cleaner just a prefilter, collecting dust maybe 5-10 microns and up. Reducing the restriction allows much higher throughput - visible dust will build up fairly quickly on high speed.

See my page: The Prefilter Experiments

The dust collectors are described under the headline "Holmes HAP-242 as a Dust Prefilter." This is easy to do, just stuff the polyurethane foam in layers as shown, this would be good in the closet application. Realize that this type filter must be cleaned frequently, but unlike a HEPA you can see it working.

In your computer room situation, I would use a MERV 7 furnace filter with multiple layers of polyurethane foam prefilter, cut down to fit in an existing air cleaner chassis.

Assuming you do not want to do this, let's see what the market has to offer as an off the shelf solution.

You don't really want a HEPA filter, automatic air sampling, remote control, or costly carbon for chemicals/odors.

Since this is a computer room, you want low noise emissions and high throughput.

Very few air purifiers fit the criteria.

The Whirlpool line is back on the market after a suspension during the 2009 slump. Model AP45030K is the current 450 series, a good dust collector without many frills, retail is $229. This model has a charcoal impregnated mesh prefilter, not quite as good for dust as the washablefiberglass screen type found on Japanese models. Whirlpool AP45030K is a good choice for dust.

Rabbit Air 421A, $329, and 582A, $399, have the fiberglass type washable screens, but have bells and whistles unnecessary for dust.

Another option is the electrostatic type, represented by the Friedrich C-90B, $399. These are good particle catchers with high throughput, and have a screen type prefilter. C90B has an industrial appearance and the occasional electrostatic crackling noise, and must be cleaned frequently to work well.

One inexpensive dust collector is the $45 Hamilton Beach 04383 Allergen Reducing Air Cleaner, see post;

Hamilton Beach 04383 catches dust.

The modifications described above will yield best results on dust, at a very reasonable price.

Best wishes,

Ed

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