DIY Air Purifier

3 minute read Published 10 February 2022
Tag icon hardware Tag icon cad Tag icon 3dprinting

A simple air purifier made with an off the shelf HEPA filter

After the recent air stagnation advisory in West Washington, I was interested in improving indoor air quality in my home. Big Clive’s video DIY cheap & quiet HEPA air cleaner gave me the inspiration I needed to get started on my own air purifier.

Parts🔗

All I needed was a filter and a fan to attach it to. For the filter: a VortexAir True HEPA Filter from Home Depot. For the fan: a spare case fan in my closet from a past PC upgrade.

VortexAir True HEPA Filter VortexAir True HEPA Filter Noctua NF A-8 PWM Noctua NF A-8 PWM

I soon realized there were a few parts I hadn’t thought about – the fan needed a power supply, and it didn’t make a seal with the filter so I needed to make some kind of adapter.

Luckily, I happened to have a USB 5V to 12V DC converter on hand which fit the bill.

Voltage converter

With my novice OpenSCAD skills, I modeled and 3D printed an adapter to mount the fan on top of the filter. Air is sucked through the filter’s fins, up, and out the top.

Adapter model

Bearings🔗

Big Clive’s video discusses one major concern with running case fans in this orientation: bearings. Common case fans use steel ball bearings to run smoothly and efficiently. However, this is a major shortcoming for the air purifier design. The orientation of the fan means the fan blade weighs down on the bearings in a way they weren’t designed for. So the lifetime of a fan with steel ball bearings would be severely reduced. Thankfully I was in the clear on this – the fan I used has a special “SSO2” bearing that is hydrodynamic and stabilized by a magnetic field. Friction is greatly reduced in this environment so orientation does not significantly affect the fan’s lifetime.

Final Product🔗

And for the finished air purifier:

Air purifier on the floor plugged into the wall

The parts used:

The total cost was $61.84. This is $38.15 cheaper than the filter’s namesake air purifier and was a fun project.

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