I purchased two of these little Air purifiers last year but with some trepidation. The system is simple enough, the unit plugs into any regular household electrical plugin which immediately begins to circulate a fan inside. The unit is whisper quiet. The size of the unit bothered me at first, I had my doubts that two together would work in the area which I wanted to use it let alone one.
Our master bedroom is quite large by most standards and given that each unit was only $6.00 and came with one filter, I figured that if they proved ineffective in this large space, I could simply move them to smaller rooms such as the downstairs powder room or better yet, the children's bath (always a treasure trove of scents going on in there). Our master bedroom is almost 800 sq ft I believe which makes the childrens bath approx 400, so I don't think that room will be much of a challenge to this unit.
Surprisingly, after plugging in just one of the units and allowing it to run for a few hours, I was able to notice a difference. The air actually did appear to be fresher and as my husband has forgotten he isn't outside and has lit a cigarette in the bedroom now and then, even the smell of such indiscretions was barely noticeable after running the unit for as little as 30 minutes last winter.
The entire purifier measures just under 8" tall by 2.5" wide with slots running the full face of the unit horizontally and vertically. Plugged in it sits about 1" out from the wall. Inside is a small foam filter about 1/4" thick. Surprisingly, the little thing has actually sucked in dust and possibly smoke (hmmm, only a few forgetful moments? I wonder).
Yesterday, I plugged the unit in at around 11 a.m. and by 2 p.m. it was noticeably a better quality of air. We run the central air a fair bit during summer months which means our windows are closed on days when it is hot or humid out. There isn't a huge amount of bad air to purify by any means, so I am quite pleased with these over all.
Replacement filters were available for $2.99 each, I purchased 4 at once. On top of the unit is a dial which you set to the month in which you begin to use it. The filter is expected to last for 2 to 3 months depending upon how quickly it becomes polluted. As the filter dirties, the dial gradually moves to the projected replacement month. I used this for a few months after purchasing but not on a regular basis. According to the dial I am good until the beginning of August before a filter change is necessary. As the filter contains a thin charcoal layer inside, washing it may not be conducive to a second round or at least not work nearly as effectively as a brand new filter.
Although I wouldn't expect the unit to last indefinitely and I don't run it during the night for safety reasons, I've not noticed any indication that it is over heating or getting hot at all. For the money I think I have gotten a reasonably effective product for my money.
The only reason I've rated the filter reminder system lower is that I am not certain just how accurate it is but as I've not changed the first filter that came with the unit yet, I'm willing to assume I'll make it to at least the middle of July if I choose to run it regularly.
Sometimes pretty good things are inexpensive and small things can indeed be effective. All in all a good purchase.