We got a Winix air purifier, I think it's
this model, although they have a proliferation of similar devices in each range. We'd looked at the 5200 / 5300 / etc models, but it was impossible to get one in white, and we wanted white, and we didn't want to repaint the thing. I considered building a cabinet for it, but then we saw them discounted sharply at Costco, in white, and so we bought one.
Seems to be good. It's got four fan settings, and the lowest two are almost silent. We've left it on continuously, so we haven't tried the Auto setting that increases the fan speed when the air seems dirty.
There's some fancy tech involved, but basically this is a very quiet, efficient fan that pulls air through a custom furnace filter. If the filters ever become expensive or discontinued, it's just a rectangle, and you can cut a regular furnace filter to size. The pre-filter is washable. It has a charcoal filter, which is nice but not crucial.
Our house is only 660 sq ft, but you'd need two of these for anything larger, I think, or to run it at high speed. Overall, I approve of this product, to date.
