Make your own air purifier and impress your friends!

Post date: Jun 4, 2013 3:36:25 PM

I hate spending a lot of money on things that can be engineered cheaply and more efficiently. Take air purifiers, for example. It seems the sweet spot in price/value for a retail air purifier is about $130-$150. Replacement filters for one can run up to $100/yr! They're also as noisy as a fan anyway, so why not just filter a fan? My wife and son both suffer from summer allergies, and after a week or so of sneezing and sniffing I decided we'd better do something to improve the situation. At Walmart, I found a Holmes air purifier for $129. It has three sets of filters in it, each one looks like a modern automotive air filter. They come in packs of two for about $40. Out in the main aisle, there were box fans for $16.88...

It turns out woodworkers have been using filtered box fans for a while. A standard box fan is 20"x20", and guess what? that's the same size as a retail furnace allergen filter. Next to the expensive air purifiers, I found an allergen furnace filter for $16.88. The issue lies in attaching the filter to the fan. Googling for "box fan filter frame" nets you many results. There is a commercial product that simply screws to a 20" box fan that holds 16"x16" retail filters, but it costs about $35. I would also prefer to use the full 20"x20" filter for increased air flow. The most elegant solution I found utilizes vinyl siding j-channel to create a slot for the filter to slide into that's attached to the fan. I discovered that my local Home Depot doesn't carry this piece in stock so for the meantime, I just taped the filters to the fans. Tape is most definitely not an elegant solution, so I'll try a Lowes in a neighboring town to see if they carry 1" vinyl j-channel.

Anyway, here's a pic of what I picked up, and a pic of the filter taped to the box fan. Not quite as pretty as a retail air purifier, but we have some inconspicuous places we can place them while they're running. Also, I was able to purchase four of these rigs for just slightly more than a single air purifier. And in my experience, these move MUCH more air than a purifier. I also think it's a bit ironic that I passed on the Holmes air purifier, and instead bought Filtrete filters endorsed by Mike Holmes.

The sneezing and sniffling in our house began to lessen within a few hours.

Once I get some j-channel, I'll update this post.