Gallery: DIY: Make Your Own HEPA Air Filtration System for Just $30!


For some of us, allergens are our worst enemy — the fresh pollen of spring, fall foliage, and of course the ever present dust, mold and animal dander. Sometimes the only solution is a high-tech air filtration system, but these complex systems can cost up to $800. But if you’re an allergy sufferer, today is your luck day as Dr. Jeffrey E. Terrell of the University of Michigan Health System’s Sinus Center shows us how to make our own easy air filtration system, for just $30!

Cleaning the air in our homes, especially the bedroom, is imperative to avoiding sinus problems and other allergy related side effects. High Efficiency Particulate Air filters (HEPA) are what doctors suggest for optimal results, but they can get pricey. Luckily, a comparable DIY solution can be found at your local hardware store. Terrell suggests first buying a twenty inch by twenty inch box fan, which usually run around $10-15 (unless you are in New York, which will run you about $20).

Then head to the furnace and heating section, and pick up a twenty by twenty furnace filter. There are many qualities of filters, so it is important to make sure that the filter is both a HEPA filter, and that it has a MERV (Minimum Efficiency Reporting Value) rating of 13 or higher. This will be indicated clearly on the packaging, and cost around $15. The rest is easy, just tape the filter (arrows out) to the face of the fan.

Just note that your DIY purifier will be more effective on the floor, rather than in a window, because it will then filter out air in your home, rather than from the outside. Terrell recommends keeping windows closed, and to simply buy another filter when the color turns from white to brown. Your new DIY system can filter allergens up to 90%!

+ University of Michigan

Via Newswise


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  1. Zayd Khan March 3, 2015 at 6:01 pm

    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.

  2. rzmacdonald February 18, 2015 at 8:09 am

    WOW!!!! THANKS!!!!

  3. woodznutz December 19, 2014 at 9:08 am

    I used this system some years ago when I spray painted
    the non-removable part of the metal baseboard hot water heating radiators that badly needed refinishing. The fan/filter captured the spray paint \’drift\’ perfectly (although I still had to wear a respirator and thoroughly air out the apartments). I painted a short length at a time keeping the fan close. Beautiful job with no overspray getting on anything. I use this system in my woodshop (a new filter turns \’yellow\’ with fine wood dust very quickly) and my home. I leave the fan on 24/7 on low speed. It draws little electricity and is virtually noiseless.

  4. zephyrprime August 14, 2014 at 3:32 pm

    If you do this, get the box fan with the most blades on it. Don’t go cheap. This will allow you to get the highest static pressure in a flow restricted environment. Also, don’t use the sucky filter this doctor used in the video. The filter was 13merv which is good but it had very few pleats and was only a 1″ thick filter. You can buy a 5-6″ filter will many more pleats which will work a lot better. Also, put the filter behind the fan rather than in front of it. Although fans can usually develop more static pressure pushing air into a filter than pulling from it, having the filter behind will allow the fan to blow air out with much higher velocity. In the real world, you need a lot of air circulation clean the air in a room. High filtration is useless if the fan is only capable of accessing the air within a short radius of itself.

  5. wesatie42 April 17, 2014 at 7:07 pm

    I do some hobby woodworking in my garage inspite of tough allergy issues. To clean the air they sell $300 dollar filtration systems but mine is shop built. I got a squirrel cage fan out of an old furnace then built a box to house it. On the inlet side there is a slot opening to the side that holds four filters. Just a 99 cent fiberglass filter are the first two filters then a couple of progressively tighter filters follow. Those motors are usually four speed so I setup a couple two gang light switches to allow speed selection on the four motor windings. It worked amazingly well and soon found the garage workshop was by far the most desirable breathing environment in my home. Have since moved and left that fan there because the new owner put that in the offer. I will build probably two of them to use here now. The cost was about $75. But I am well impressed with the results for the cost. Currently am using a Holmes in my bedroom to take the edge off of my breathing problems but sure look forward to having a replacement ready for my shop built furnace fan. Clearly it can produce a large air flow depending on fan switch selection.

  6. Matty Pantaloons October 31, 2012 at 3:33 am

    Thanks a lot for this post. I ran out and bought a decent filter tonight and I notice a difference in air quality already. Up here in Montreal, winter means closed windows, and for a person allergic to dust mites, the season can be lonnnnng…

    I already had a 20×20 box fan, so only needed the filter. Unfortunately, most of the filters where I went were MERV 8, and many other didn\’t have MERV rating; instead have MPR (Micro Particle Performance Rating).I picked up a 3M Filtrete 1900 (1900 MPR), which has about the same filtration as a MERV 13 from what I\’ve read.

    However, none of these filters are HEPA, and I saw a *lot* of furnace filters where I went. From what I understand, HEPA filters create too much resistance for furnaces, but high MERV rating filters do the same job, with the exception of virus removal.

    Also, I attached my filter to the back of my box fan instead of the front. Better to *pull* air into the filter, without cutting down on airflow from the front of the fan.

    Again thanks for the post, fantastic idea.

  7. hodgebodge May 10, 2012 at 3:11 pm

    I made one of these box fan + furnace filter contraptions and posted some info about it here:

    I used zip ties, which seems to me to be a better way to go than tape.

  8. caeman July 11, 2011 at 9:19 am

    The filtering would depend on the quality of the filter you buy to fit to the fan. I suppose one could tape a filter to both sides of the fan for double-filtering. A looser intake side, and a stricter out-bound side.

  9. cthue July 11, 2011 at 3:47 am

    I’ve have been looking for a small HEPA system, but most of them are over the $100USD, this looks like a cheap and simple idea, that claims to filter up to 90% of allergens.

    * I wonder if you might use it on the lowest speed. You may don’t want to over heat the fan motor.

  10. caeman June 30, 2011 at 3:54 pm

    Such a simple, yet brilliant, solution to keeping the air in our homes clean.

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