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.
VortexAir True HEPA Filter 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.
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.
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.
And for the finished air purifier:
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.