Washable, Homemade Filters for Clean Indoor Air

by Sarah TheHealthyHomeEconomist

washable homemade filters
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 homemade filters!

How to Make Healthy, Homemade 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 homemade filter that allows the free flow of hot air while offering a hygienic filter.

These homemade filters are as good, if not better, than any pre-made filters from the store and are easily tossed into the washer monthly, so you and your family can breathe freely and not spend a dime!

When the furnace first comes on in the cooler months, clean the filters more often, perhaps even have a few of them already made and fitted.

In your little girl’s room, choose a pink sweater. In your son’s, blue.  Homemade filters can color coordinate too!

Simple solutions for a healthier life … made by you.

Our health is in our hands!

For more information on clean indoor air, this article explains the top 10 house plants proven by NASA to filter toxins out of the air that are outgassed from building materials and household products.

About the Author

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.

Photography Credit


Comments (42)

  1. You may be having a bad air day every day — and we are not talking about outdoor air. The indoor air quality in your home may be affecting your health and the health of your family members.

    “Indoor air quality can be worse than outdoor air quality in almost every case,” says William J. Calhoun, MD, professor of medicine and vice chair of the department of medicine at the University of Texas Medical Branch in Galveston.

  2. Cheesecloth allows more air to move through but still catches plenty of dust etc. It’s easy to cut to size, you can make it as thick or thin as needed, too. If you put filters on the cold air return vents as well, it keeps the dust/pet dander etc from going back into the system.

    • Why would putting the “sweater” filter in the vent opening cause any more strain on the blower motor that closing the register vent would?

  3. I am going to side with the HVAC technicians on this one (I’m not a HVAC person). This does not sound like a good idea because it will put strain on your blower motor in your furnace. While I just love the ingenuity of this idea, I don’t think it is a good idea for the health of the furnace. They’re very expensive to replace. I’m not sure the cost of just the blower motor, but why spend lots of unnecessary $$$ to replace one because the motor burned out early?

    If you want cleaner air in your home, here are 3 safer ways to do this:

    * Use good quality furnace filters and check or replace them every 3 months. If you see lots of dirt/dust, replace with a new one, if not check again in 3 months. These are the square or rectangular filters that go inside your furnace. This is probably the most effective thing you can do to clean your air in your home AND keep your furnace functioning properly. Any of the pleated style filters work well, avoid the loose fiber kinds. 3M makes some of the best ones, but are overrated, in my opinion. Store branded pleated filters work nearly as well as the more expensive 3M ones. This tip is a “must do”, whereas the following two tips are optional. If you don’t change your furnace filter regularly, you’re circulating dusty air through your home as well as putting undue stress on the furnace itself.

    * Have your ductwork cleaned professionally every couple of years. Costs run around $200-$400 for a quality clean job, depending upon your location. This is more important if you have pets, because pet dander will fall down into the vents (if the vents are on the floor) and will get blown back out next time the heat or AC comes on.

    * use an air filter machine in the rooms you most frequent, or simply move one machine around to a different location every few days. HEPA based filter machines clean the best, but even a cheap filter machine will do a lot of good cleaning the air. A bigger machine can generally clean more air with less noise. Check filters every 3 months when you check the furnace filters.

    Now, I do believe there are WASHABLE furnace filters, but I have not used them. I think your furnace must also be designed to work with them. Perhaps someone knows more about these than I do. My general experience with washable filters (vacuums, etc) is they sound better on paper than they work in real life.

  4. 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

  5. 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. :)

  6. 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.

  7. 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!!!!!

  8. 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.

    • my hubby also a HVAC Tech. i asked him after reading. Says better to take the 1″ filter out of your intake, replace it with a 4″ pleated one. increase is about 80% reduction of stuff coming thru your system. You only need 2 of them a season here in NY. my hubby is big about no more then 2 floor vents close all the way in our house at a time. 14X70 home. so covering them would over heat your furnace. Go ahead NY do it. I love his overtime. lol

  9. 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!

  10. 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.

    • i looked up Norwex Microfiber. It’s suppose to be used to clean your face and clear up acne. Is this what you are talking about ? And if so, do you use detergent or cleanser for your dusting and cleaning with it. What kind of cleanser do you use?

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  13. 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.

  14. 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.

  15. 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?

  16. 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.

  17. 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! :)

  18. 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.

  19. 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?

  20. 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?


    • i would use two sheets of chicken fence the wool cut in the middle, make sure the sweather is not too thick so it would not mess up the flow of the air.

  21. 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!!

  22. 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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