Homemade Filters for Clean Indoor Air

by Sarah TheHealthyHomeEconomist December 15, 2011

Simple sweater from NZ knobbly wool
Guest Post by Joette Calabrese, Classical Homeopath, HMC, CCH, RSHom

Snow is falling, cold wind is blowing.  The furnace clicks on.

Uh oh!  What about all that dust and dirt and who knows what else that has collected in the air ducts over the past months?

Here’s a simple solution for keeping the dusty and even moldy muck from spewing into your air and into your lungs when you breathe.

Make your own washable filters!

Find an old 100% wool sweater; perhaps at your local Salvation Army and wash it in hot, hot water and simple soap in your washing machine. This is not a time to worry about the delicacy of the sweater. We want it to felt up good and thick, even shrink.

The idea is to tease the fibers into felty submission. Then dry it in a hot dryer. This will further the felting process. Once the sweater is thick and misshapen, measure the perimeter of the register (the opening on the floor where the heat blows out) and cut the sweater to fit neatly into the opening.

The best part is that you don’t need to hem the ends since felted wool doesn’t fray.

It will make a tidy filter that allows the free flow of hot air while offering a hygienic filter.

This wool filter is as good, if not better, than any pre-made filter and is easily tossed into the washer monthly, so you and your family can breathe freely. When the furnace first comes on in the cooler months, clean the filter more often, perhaps even have a few of them already made and ready to fitted.

In your little girl’s room, choose a pink sweater. In your son’s, blue.

Simple solutions for a healthier life…made by you.

Our health is in our hands!

If you yearn to learn, contact Joette Calabrese at HomeopathyWorks.net for a free, 15 minute SKYPE or phone session and find out if homeopathy is a good fit for you and your family’s lifestyle strategy.

For a download of our new, printer-friendly First Aid Chart, go to www.homeopathyworks.net and find it in the “Free Downloads and Articles” box. Don’t forget to check out all the information on Joette’s upcoming system designed for moms. Just click Yearn to Learn.


Picture Credit


Comments (35)

  1. Sharon Lee Lockhart via Facebook February 13, 2014 at 8:17 pm

    I like this idea. I don’t think it would make the furnace run hot, nor do I think it would burn up the motor. I think the wool sweater is a great idea and one that the next time I am out and about, I will look for just the right sweater to do this with. WOW, no dust, that would be a great thing in our old house. LOL

  2. I had to reread the article. Note that it is not ‘furnace filters’ but the ‘floor registers’ in each room. I can understand the mix-up because I misunderstood as well. :)

  3. Paula Jean PInciaro via Facebook February 10, 2014 at 10:25 pm

    Better for your home, family, respiratory, etc. is to have the duct work cleaned.
    It can be done affordable, removes dust, and kills mildew or mold inside.
    And it does not hinder the air flow necessary to keep the furnace running efficiently.

  4. Amy Callahan via Facebook February 10, 2014 at 10:17 pm

    This does not sound like a good idea for your furnace! it needs air to flow and not get stopped. this may cause it to work extra hard and never get your home heated to the desired temp on the thermostat. Be careful!!!!!

  5. I wouldn’t try it. It will cause strain on your furnace and/or AC and may cause it to burn out and thousands of dollars worth of damage. This is per my husband who is a HVAC technician.

    He says it’s a terrible idea that will ruin your equipment. And we know how costly furnaces are. Friends of ours had theirs recently replaced (previous was old unreliable system) and it cost them $6,500.

    That air that someone was complaining is not coming out of the vent us pressing back into the system causing motor, fan, and pump to strain, overheat, etc.

  6. I was so excited to do this today, but when we turned the furnace on, no air was coming out! Can someone please help????? My husband was not a fan of my trying this, ha!

  7. Love this tip! Thank You :)
    We don’t have to clean our furnace filters too often because I use the Norwex Microfiber for my floors, dusting and cleaning everywhere. Since I started doing that the filters don’t get dirty as quickly. We are allergy sufferers though and every little bit extra helps. Are you familiar with Norwex. It would probably be something you would love. No chemicals and it still removes all the Bacteria.

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  10. This application is used at the vent, in each room, not anywhere near the furnace. So I wouldn’t call it a furnace filter, but a duct filter. In the houses where I’ve lived, the vents are on the floor and are sometimes called registers. lift up the heavy metal grate that covers the opening to the duct and place the wool flat at the mouth of the duct, making sure it is the exact size of the opening. then replace the metal grate directly atop of your filter. It indeed may make the amount of heat blowing through the grate less efficient, but the heat that is forced thorough will be cleaner.

  11. Hearts Home via Facebook December 15, 2011 at 4:42 pm

    she’s just saying to put it in your heating vent where the heat comes into your room. Not the furnace filter.

  12. Aron Baier via Facebook December 15, 2011 at 3:57 pm

    Can you explain exactly how this works. I am having troubles picturing it. I understand how to felt sweaters, but not how to actually use it as a furnace filter. The blogger is talking about using it to replace actual furnace filters correct?

  13. Flavia Sordelet via Facebook December 15, 2011 at 3:50 pm

    Great idea! I hate using the central heating, even as year-round Tahoe residents we use the wood stove as the primary heating source.

  14. What a fabulous idea!!! I can’t wait to try this! I once called and asked how much it would be to have my heating pipes vacummed out and it was going to be over $600! What a great and economical solution. Especially where I live in Alaska. We use the heater for 6 months! Thank you Sarah! :)

  15. I wonder if this would pose a threat to the functionality of the furnace, it is always advised not to even close registers because then it pushes more air through less vents.

  16. Thanks! My brother and I always had allergic reactions to the constant presence of mold, mildew, and dust in our house. Especially since its so old. I may also try this with the A/C in the hotter months.

    • Bernice, when we moved into our house, they had blue fiber filters in all the vents. When we had everything checked out the heat a/c guy immediately told us to remove them as these make the units less effective. He recommended instead getting a good whole house filter where it was designed to be on the unit and to make sure to change it quarterly. I’m wondering if there’s a way to make a washable air filter for the main filter slot?

  17. Would we need to attach the sweater to some sort of “frame” in order to allow the soft material to be firm enough to fit all the way into the register without crumpling all up at one end? My register is 16x25x1 and there is no way I could get a wool sweater to fit all the way into the register without some support. Any suggestions?


  18. wow thank you for this post so much!
    I have dust/mold allergies which got a lot better since I took a course of strong probiotics, but we still have 3 HEPA filter air purifiers in our home to keep me from sneezing!
    I am off to a local thrift store tomorrow to find a 100 % wool sweater to do this!!

  19. I bet this would work to replace the a/c filter too. Living in FL the heat only gets turned on during the quarterly system cleaning, but I’d love to get rid of those horrid pleated paper filters without the loss in quality we’ve experienced from commercially available washable filters.


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