Turn a Hair Dryer Fan and a Drain Pipe Into a Working Air Prufier

Looking for a simple, low-cost way to build your own air purifier?

In this project, I demonstrate how to make a compact HEPA air purifier using a drain pipe, an old hair dryer fan, and a repurposed filter cartridge. This build is perfect for small rooms, work desks, or dorm setups. The best part? It's made almost entirely from recycled materials and runs on low voltage!

The fan pulls air through a perforated PVC housing and forces it through a filter compartment, removing dust and small particles from the air. It's an easy weekend build for makers who love mixing upcycling and clean air tech.

Perfect for:

- Electronics tinkerers

- Reuse enthusiasts

- DIY clean air projects

1x PVC Drain Pipe Coupler (Ø 100 mm or similar)

Used as the main body of the filter housing.

2x PVC End Cap

To seal the back of the housing and hold the fan motor.

1x Small Electric Motor with Fan Blade

(Taken from an old hair dryer.) Provides airflow.

1x 12V Power Supply or Battery Connector

To power the motor. (Use what matches your motor voltage.)

1x HEPA or Activated Carbon Filter Disk

You can cut it from a used vacuum filter or buy a generic round filter.

Electrical Tape or Heat Shrink Tubing

For safe wiring and insulation.

Hot Glue, Epoxy or Strong Adhesive

Used to secure motor and seal connections.

Sandpaper (Optional)

To smooth PVC edges or surface for gluing.

🛠️ Instructions:

1. Drill small holes around the side walls of the pipe and on the front cap (a 2.5–3 mm drill bit works well).
2. Disassemble the hair dryer and carefully extract the fan motor.
3. Wrap EVA foam around the perimeter of the fan housing until it fits snugly inside the PVC cap.
4. Use strong adhesive to bond the EVA foam to the inside walls of the cap.
5. Ensure the fan blades spin freely and remain well-centered.
6. Keep the motor wires exposed and ready for connection to the power supply.
7. Test fit all components before applying any glue. The fan should direct airflow through the filter and out the top.
8. 
   
9. Optionally, sand the PVC edges to remove burrs and improve adhesive bonding.

🛠️ Instructions:

1. Drill multiple small holes all around the side walls of the PVC pipe using a 2.5–3 mm drill bit. These holes will allow air to enter the filter chamber.
2. Cut an EVA foam sheet to fit the inner diameter of the pipe. You can wrap it into a cylindrical shape or use a pre-cut circular disk.
3. Insert the EVA foam filter inside the pipe and press it into position. It should stay snug and not block the airflow.
4. Ensure that the filter surface faces the intake holes and that air can pass through it freely.
5. Optionally, use a small mesh or second filter layer to improve filtration.

NOTE:At the time I was designing and documenting this project, I did not yet have the HEPA filter. To keep building and test the airflow, I used a piece of felt as a temporary filter. While it doesn’t match the filtration efficiency of a true HEPA filter, felt is better than open foam for catching large dust particles and allows for early-stage testing of airflow and structure

Final Step: Power It Up and Breathe Easy!

Once everything is assembled and the filter is in place, simply connect the fan wires to a 12V power supply (or a battery, if that's your setup), and you're done!

You now have a fully functional DIY air purifier, built from recycled materials and customized to your own needs. It’s quiet, compact, and perfect for small spaces like a bedroom, study corner, or workspace.

💡 When your HEPA filter arrives, just replace the temporary felt layer and enjoy even cleaner air.

Thanks for following along!

If you build your own version, feel free to share your results or improvements. Happy making!