Michigan Medicine
5 HN recommenders · recommended in 9 months, 2012–2022
3:40 · 2.3M views · Jun 27, 2011
A University of Michigan Medicine demonstration of building a cheap DIY air purifier from a box fan and a HEPA or high-MERV filter using hardware-store parts. It explains why this helps against dust, smoke and viruses and ties it to local air quality readings.
HN people link it during wildfire smoke and air quality threads as a practical, cheap fix, though a few doubt how rigorously its effectiveness was shown.
11 comments from Hacker News
If you are worried about particulate, you can build one of these: this video I built one for my room because my previous tenants had cats, which I'm allergic to. Even after steamcleaning our apartment I was chronically congested. Built one of those purifiers and a few days later most of my symptoms are gone. It's been about a month now and the filter is noticeably soiled.
The University of Michigan made an instructional video showing how you can easily make an air purifier out of a box fan and a HEPA-rated furnace filter for $25: this video It won't be as good as a purpose-built machine, but it will be far better than nothing at all. TheWirecutter found it reduced particulate matter in a room by 87%, if you do it right. They also make clear important caveats about this method -- in short, this works in a pinch, but probably should not be used in place of a purpose-built filter if you want one for year-round use. [LINK]
Yeah, same thought. Something like the Coway air filter ( [LINK] ) regularly sells for under $200, and it is going to be much quieter than this option. It also has been tested fairly extensively from what I've seen, it's EnergyStar approved, etc, and it has a built in sensor. It doesn't look too bad either. But I understand the point, especially in times when you can't find a purifier. Also, good video on all this: this video
If this is because of high PM2.5 concentration (due to wildfires or otherwise), I suggest building a DIY air filter, such as the one in the video here: this video When the Air Quality Index shot up to ~150 in my area (you want to keep it below 100, preferably below 50), I went to Home Depot and bought box fans and furnace filters and built my own. You can check the air quality in your area on this site: [LINK]
Here's a video from the University of Michigan showing just how effective these cheap DIY air filters can be: this video