sweetrai wrote:Thanks for this comment. I am looking for a filter for my living room area. Is there one your would recommend? The living room is connected to the kitchen and I have pets and a toddler. Which true HEPA filter would your reccommend? I also want to put a filter in the bedrooms.
Depends on what you are trying to solve. If it's just general odors and large dust, anything with either activated carbon or an ozone-free ionizer and a dust filter will work. Sharp Plasmacluster comes to mind.
If you have medical needs for particulate free air, get something with True HEPA or even Hyper HEPA. These units cost more, the filter replacements are expensive, but they work in a very raw and mechanical fashion by pulling air through a filter. The best on the market would probably be an IQAir filter, but those run around $800-$1200.
Whatever you buy, keep in mind that the CADR rating is at the HIGHEST fan setting, which unfortunately is often the loudest setting as well. Also, the rated square footage of a unit is assuming you have standard 8ft ceilings and some way to isolate the room. If you have vaulted ceilings and an open layout, then the unit won't perform as rated, but will work given enough time and enough air circulation.
Honestly, though, if you have a central air system, then just get 3M Filtrete furnace filters, run the fan on the ON setting for continuous, and change the filters often. This provides a more whole-house effect since most furnace blowers are pushing at least 800-1000 CFM and you're already used to the noise of it running.
These portable units are really only useful for closed areas like the bedroom, nursery, study, etc. Some of the more bulky filters like Austin Air or Airpura can process up to 2000 sq. ft, but will be very loud while running.