So in researching air filters for my room I was very disappointed to find that not only did most of the units cost $50 or more but the annual filter replacement costs were way too much. So I made my own small quiet one on the cheap.

Step 1: Parts and Time

2 hours build time

Parts - Tools

- Cardboard box of some sort. Just big enough to fit the fans. I chose an Optorite DVD burner drive box I had lying around.
- Fans. I chose 2 blue LED 120mm fans I you can pick up at www.svc.com or www.newegg.com on sale from $10-15.
- Filter. I first tried cutting a whole house filter but it is wavy and has a metal guard so I went back to home depot and found Vent filters for about $8 for a 12 pack of 4 in X 12 in filters.
- Box Cutter or x-acto knife
- Screw Driver and included fan screws

Improvements for my next version.
- Add a switch to turn it on and off.
- Add a Fan speed control.
- Add a LED kill switch or use fans with no LEDS (Hard to fall asleep sometimes but is good for a night light)
- hook to a 12 volt DC to AC power adapter so you don't need to run a wire from the computers power supply.

Step 2: Sizing and Cutting

First I stenciled the fans with a pencil so I knew how much to cut out.
Then I cut out both holes for the fans.

Step 3: Cutting Out Filter Holes

Next I had to decide on how to cut the holes for the filter so there would be enough air passing through but still support the filter. I measured and cut the filter to size which turned out to be 6 x 4 inches. Then I measured on the box 1/4 inch in from where the filter was going to be and started cutting rectangles leaving a bar across the middle so it wouldn't be too flimsy.

Step 4: Installing the Fans

Next I poked and drilled pilot holes for the fan screws and installed the fans in place. Then I cut a groove in the bottom side where I could have the wires run out of the box without letting much air escape.

Step 5: Starting It Up

Once the fans were installed I cut the filter in half 4 x 6 to fit in its designated area closed up the box and plugged it right into my computer's power supply since it already had that molex connection.

Step 6: Results

After 1 month and 17 days I opened it up (see first pic). A month after that (see pic 2). Since then I just take the filters out and shake them outside and or vacuum them. I haven't replaced a filter yet. I don't think it is big enough or powerful enough for my whole room though. I still get dust but it definitely takes a lot longer to accumulate.