Cheap, Efficient Air Purifier

I’ve been cleaning up the basement workshop with its dust and mold and residue of lightly crumbling wall and the place is musty, enough that on humid days the odor begins pervading the upstairs rooms.

My parents gave us a dehumidifer they didn’t need and that works great. There’s a noticeable difference in air quality after it’s been running for a day.

But the basement’s still dusty, especially when I’m cutting wood or moving things around. I’m not down there enough to justify a pro-grade air filtration system like you see in serious workshops, but I definitely needed something. Shop-Vac makes an attractive portable purifier, but it’s basically a tube-shaped fan with a filter in the middle and it costs $130.

I found a cheaper solution on a message board a while back (can’t remember where, I’m sorry to say) and this morning I went for it. You take a $20 box fan — something without a motor on the back — and rest a $10 fine-particle furnace filter behind it. Make sure you place the filter in the correct direction; the airflow should enter through the open cottony side, not the side with the wire-mesh or cardboard support. Wha-la, instant air purifier.

The stronger the fan, the better it works, but even with my basic box fan, it’s pulling plenty of air, and because of the suction, you don’t even have to tape the filter to the fan. It just sticks. This is why you can’t have a motor on the back, by the way; it would not only prevent a flush fit, it could potentially heat against the filter and become a fire hazard, especially if you’re using a high-velocity fan.

This isn’t meant to replace a regular Shop-Vac hooked directly to a table saw, however. That kind of dust needs to be captured directly, but it ought to work to catch the motes and spores and freshen things up. Even if you have to buy a new fan, the whole deal is $30, and you can replace the filter as often as needed.