Sharp FP-A28UW Plasmacluster Air Purifier

I've been looking for a solution in my bedroom to clean the air and supplement "white noise", this product has met my expectations.

I've always slept with a fan to make background noise, and noticed that over time dust would accumulate on the blades and fan grate. After cleaning the fan the last time, I strapped a furnace filter to the back of the fan simply to keep the fan cleaner longer. The furnace filter had taken a LOT of dust out of the air. It was then that I decided to look for a better solution.

I am intrigued by the Plasmacluster claims of "adding moisture", "killing airborne microbes and virues" and "removing odors", but one thing doesn't make sense: the positive and negative ions the same ones found in nature are what is responsible for these effects? Does that mean that you could simply open the window and let some fresh air in? If they are claiming that the Plasmacluster technology can be used as a substitution for an open window, I am impressed.

I disassembled the unit and it is very simple inside: a blower, and a little Plasmacluster module facing into the blower. On the back is a white plastic cover with rounded holes and a fine mesh pre-filter. Open the cover and you can remove or replace the HEPA style filter: it is 11.25"x12.25". Sharp claims that it will last 2 years; I cannot find a replacement right now, hopefully they will be available when I need one (or I may find a retrofit or design my own).

I can hear the Plasmacluster Ion generator when its turned on, on low fan speed it sound like its turning on/off several times a second (sounds like a flutter), on medium fan speed it turns on/off every second (sounds like a vibrating cellphone in the couch), and on high fan speed you can't hear it over the fan. Low fan speed is very quiet.

This Sharp Plasmacluster is a "High Density 7000" unit. If you're more interested in the Ion technology, you should look for the units labeled "High Density 25000". Otherwise, I am not sure if I can recommend this product to you... I like it, but I don't "notice" the ions. I do know that it is turning the air over 4 times per hour in my bedroom (on medium), and I think it makes a difference when I sleep, but I don't think this is the most economical solution. I do not suffer from allergies, but I know the air in my room is cleaner. If Sharp can provide me with an excellent warranty and/or long service life, then I can recommend it. (one last note, its made in Thailand, not Japan)