An air purifier that takes standard furnace filters?

February 21, 2016 6:33 PM

I'm looking for an air purifier that I can put a standard size (even if it's small) furnace or other standard and readily availible filter in. Do these exist?

I use an air purifier in my house to both trap dust and cat hair, as well as generate white noise. My last one was okay, but the filters for it were $80.

What are my options for an air purifier that doesn't use expensive/proprietary filters that I can just get at a hardware store?

posted by bensherman to Home & Garden (6 answers total)

As far as I can tell most (all?) home filters are going the Gilette give-away-the-razors, sell-the-blades route, but if you do some quick searches for "air filter hack" you'll find a lot of different options for cutting open existing filters and replacing them with filter materials for a tiny fraction of that cost. Here's one example.

There's other options: here's someone from the University of Michigan observing that a cheap box fan and HEPA-filter are both about 20"x20" so a piece of bent sheet metal or some duct tape will set you right up.
posted by mhoye at 6:57 PM on February 21, 2016 [2 favorites]

I have tried the cheap box fan + 20x20 furnace filter, and it is very satisfying white noise and does seem to help with the smell of cooking food/dog/musty funk in our house even though it doesn't trap 99.99% of particulate like expensive filters.
posted by muddgirl at 7:25 PM on February 21, 2016 [1 favorite]

You could get an air purifier with a permanent washable filter. I don't use an air filter but there are lots of options online at different price points. Another search term is "permanent filter."
posted by Crystalinne at 8:57 PM on February 21, 2016

My husband used to own a carpet and air duct cleaning company and swears by the cheap-box-fan 20x20-furnace-filter solution. you don't even need to tape the filter to the fan, just hold the filter up against the back of the fan, and the air pressure will grab the filter to the fan by itself. We change our filter every couple of months, and comparing the old one to the new one is revolting.

If you want it to capture more particulates, buy a higher quality furnace filter, and periodically move the filter to a different spot in the room. We have one running 24/7 in our bedroom and despite living in the desert, we have very little dust in the room. (Want to see something scary? Set up a box fan and filter, then burn a candle in another room. The filter will be visibly grey within hours)
posted by antimony at 10:30 AM on February 22, 2016

We also do the box fan thing with the really thin and cheap filters from Wal Mart. (We get them in a pack, I think they're less than $1 each.)

We trap a lot of dust with these. We change them every couple weeks and they're pretty filthy at that point.

It's a cheap thing to try out for yourself and see if it makes a difference.

I agree with moving the fan around the room and/or house.
posted by mattu at 11:59 AM on February 22, 2016

Here's a before and after photo. The filter on the right is about 2 months' worth of air filtration.
posted by antimony at 8:00 PM on February 22, 2016 [1 favorite]