Air Filter for Your Room on the Cheap





Introduction: Air Filter for Your Room on the Cheap

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 or 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.



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    45 Discussions

    Well you can canabalise more PC fans, build a bigger box that you can attach to your open windows. That should reduce the dust coming from the windows almost completely. Now you need only worry about the dust from the rest of the house. Oh and power that sucker by a solar panel, wont const extra in electricity.

    PS if dust comes from your MS Windows installation, I think MS have a huge problem hahahahaha

    use a $10-$12 dollar 9" box fan from Walmart instead of PC fans, Molex connectors and adapters
    otherwise setup the same with filter and cut out box
    total price under $20 bucks

    Great tutorial! I needed to make just the HEPA filter though. If you want to see how to make just the filter for your air purifier, here is a video.

    I found this

    That might help so that you can place it near an outlet rather than a computer.

    Why not use a 3 Fan USB Notebook Cooling Pad works with usb Power ..You can just modify the box like shown by Toadman03.....

    What is the significance of this air filter to oneself and the community?

    I thought the idea was to have a quiet air filter, not a noisy air pusher! But since I don't mind the sound of a fan, I might just stick a big filter on the back of a box fan.

    Not counting the recycled DVD-RW drive box and the tools, about how much do you think you spent on this project? And for those of us computer users who aren't computer engineers, what's a molex connection?

    6 replies

    I spent about $7 on the 5 pack of filters and the fans on sale were $10 or $12 each so in total under $20. A molex connector is the power plug that connects to your cd drives and older hard drives it is a smoke colored plastic piece with 4 wires 2 black grounds one red 12 volts and 1 yellow 5 volts. You can see 4 of them in the picture under Step 2 connected to the wires from the fans.

     That math doesn't add up. 7+10x2>20 closer to 30.

    Also, red wires go to 5v, yellow to12v.

    Any way, you can get 120mm fans for about 6 dollars brand new online. If you can find electronic surplus stores you can sometimes get them for cheaper, but it's not too common to do so.

    Ok, but it would still be 27-31 dollars spent unless you were allowed to pull out 1 and buy it for a discounted price, however 2 fans would still be 20 dollars alone. There is no way for that total to be under 20.

     A molex connector is the connector used inside a computer for providing power to peripherals, generally white, 4 good sized pins.

    Hi im new to DOY-ing and i was just wondering if you knew how to use a regular outlet for power instead of your computer's power supply

    2 replies

    you would just need to use a 5volt to 12volt power adapter or a variable one from radioshack or ebay. The ones I am talking about are from cd walkmans, wireless routers, computer speakers, etc. The computer power supply's red and black wire puts out 5 volts and the yellow and black puts out 12 volts. The only thing i am not sure about is the amperage I think you just need stay under 1amp but you should probably look that up.

    The amperage of the drawing appliances has to be smaller than the one of the adapter. E.g for an adapter that has 2 A @ 12V output you could theoretically connect 4 fans of 500 mA @ 12V. So basically the more amps the adapter puts out, the better. But also, the higher the power consumption from the 110V-220V AC in Watts. Hope that clears thing up a bit.

    when i saw the cool blue lights i thought this was going to be some ultra violet air purifier

    Good concept, but not complete without proper power instructions.  "Plugged into my PC power supply since it already has molex.", is not instructions.  But like the concept thanks.

    1 reply

    Actually, that is proper power instructions. The fans in question were designed to be installed into a computer chassis, so the instruction "plug into PC power supply" is perfect because all the voltage and resistance will automatically check out and be fine.

    If you are too chicken to pop open your computer, buy a power supply unit and just use that. Then you can have a lot of fans!