Introduction: Air Filter for Your Room on the Cheap

Picture of 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

Picture of 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

Picture of 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

Picture of 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

Picture of 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

Picture of 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

Picture of 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.


thylvin (author)2016-04-06

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

zwatcher (author)2015-05-03

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

zkhan89 (author)2015-03-03

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.

Saurian24 (author)2012-07-25

I found this

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

micca01 (author)2012-05-29

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

alibron (author)2011-11-21

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

jjohnson14 (author)2011-11-14

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.

StoryAddict (author)2009-06-22

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?

Toadman03 (author)StoryAddict2009-06-23

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.

downgrade (author)Toadman032010-04-06

 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.

ironjudas (author)downgrade2011-09-05

first 7/5 :) its a 5 pack

downgrade (author)ironjudas2011-09-11

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.

ironjudas (author)downgrade2011-09-05

but who cares? with the gas prices these days... jeez hehe.

milsorgen (author)StoryAddict2010-01-10

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

Tairanasuar (author)2009-02-25

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

Toadman03 (author)Tairanasuar2009-02-26

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.

ironjudas (author)Toadman032011-09-05

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.

pyra_builder_1337 (author)2011-06-07

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

spydercanopus (author)2010-01-03

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.

PikeMinnow (author)spydercanopus2011-02-28

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!

 And are you a smoker?

TheInventor1997 (author)2010-10-06

when r u gonna put v2 0n

We just bought a house and are getting married on Sunday. So hopefully when we get settled and moved in I will have some time to start some cool diy projects. I really want to get back into that. Thanks for the interest it keeps me motivated to do projects like this.

shopperben (author)2009-07-09

i think that it would be better to avoid "cutting" the filter material. Perhaps, increasing the box size to accommodate the size of the filter material. that way the filter material can be slipped in and out of the unit without the hassle of cutting it down and wasting the smaller portions. however, if you had smaller portions left over, you might be able to cut vents on the sides, then the air intake and filtering would be omni directional.

killprogram (author)shopperben2010-09-24

i think you mean multidirectional, omnidirectional would mean that it is cleaning in all directions whereas what you have suggested would only add two side vents allowing a better ratio between intake and outflow yes however it would be "breathing" in from 3 sides and "breathing" out from one

Danny_Payne (author)2009-07-03

could you put 2 bottles of frozen water in there to keep it cool, or would that not work?

Win7Maniac (author)Danny_Payne2009-09-28

Uh, sorry dude, but the fans aren't in there to keep it cool, they're there to keep are circulating. The air goes through the filters, dirt gets trapped. . . need I say more?

hock3ydud3 (author)2009-05-30

you could maybe do a usb power supply, and just have a dual cable thing, like some external hard drives have where you plug in two usb cables to the computer, one for data and power, and the other for extra power. that would get you to 11 volts, which should be enough

Jgatkinsn (author)2009-05-21

That rocks! You did a great job, and I can definitely see easy way to customize it to my personal needs.

carroty (author)2009-05-10

you can use a ac to dc transformer from older model printers

Dosbomber (author)2009-04-19

Maybe I've missed something, but what's holding the filter against the holes in the back?

Yerboogieman (author)2009-04-02

Less Dust though, still good.

audiolizard (author)2009-03-17

I think you meant AC to DC power adapter - like a wall wart.

ron2470 (author)2009-03-10

nice idea. i used 2 hepa filters that were very thick and i was surprised that the fans could handle them. the filters that u used are meant for vacuum vents which is most effective in dust and mites. hepa filters are a bit more expensive but filter much more. nice project. very effective for my room.

jetsmiley123 (author)ron24702009-03-12

I have a dust might allergy, and i am really pashonate about making this filter, because in this day and age i am short on money, and now i found the perfect and easy Instructable. so hepa filters work better at collecting dust mights? can you buy hepa filters at a regular hardware store, like manards? if not, where can i get them? Internet? thanks -jetsmiley

ron2470 (author)jetsmiley1232009-03-13

yes hepa filters are better at filtering dust mites. u can buy them at menards, home depot, or lowes. they are widely available localy.

multiplecats (author)2009-03-06

Howly cow - look at the dust on that filter! Nice haul, Toadman! Imagine the crud you've taken out of the breathing air for both you and your computer. Hooray! I would like to make one of your filters to sit behind my computer and gobble up dust bunnies on their pilgrimage to the tower, where they try to become one with the warm hum of static electricity. I'm in an old old house and dust is a way of life. But the storebought filter tower I have has put a good kibosh on that. A few of your cool little filters would be a welcome supplement, as soon as I sit down and figure out how to run them off the house mains. Air filters are so great. I seriously can't recommend them enough. Thanks for the Instructable!

Shadowfury (author)2009-02-27

Good idea, but will it spark?

desidude52 (author)2009-02-26

Brilliant! I have so many old computer fans and can easily find many things to use as a filter. Maybe make a box big enough to put furnace filter in.

illdoyourdrugs (author)2009-02-26

Useful. nice!

wyldchild007 (author)2009-02-20

This is a really good idea and I would like to do a similiar idea but without needing a computer to plug the fans into. Is there a way to power the fans from the household mains? Or do you think a small regular fan rather than a computer fan would work just as well? Many thanks in advance!!

Toadman03 (author)wyldchild0072009-02-20

Thanks. I'm sure you could do an actual 110 volt fan if you can find one small enough that has the force to push through the filters. The other two options are to get a power adapter from radioshack or one lying around the house that is variable or 5 or 6 volts and just hard wire the fans to it or you could always just plug in a stray computer power supply, jump the green and a black wire from the Motherboard plug and use the molex plugs to power the fan.

wyldchild007 (author)Toadman032009-02-21

Thanks for the reply! Now i have a project for today! :-)

Toadman03 (author)wyldchild0072009-02-21

glad I could help. if you are going to use the power adapter you could go up to 12 volts but for me the fans were too loud. On the fan plug in the computer is when I switched the wires from the yellow 12volts to the red 5 volt wires to quiet them down a little. Good Luck

djr6789 (author)2009-02-18

this is so kool

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