In a recent study, researchers tested household materials that could be used to make DIY masks, but they left out one common material—paper towel masks (also called “kitchen paper”). Could paper towel be an effective material for making homemade masks in times of crisis and shortages? Smart Air Engineer Paddy tested its effectiveness in the Beijing lab.
Putting Paper Towel Masks to The Test
Paddy used a Met One GT-521S particle counter to test how well a single and double layer of paper towel filtered out particles down to 0.3 microns. Paddy ran the Met One for one minute, measuring the total number of particles passing through the kitchen paper versus the same setup with no filter.
How Big Are Viruses?
Just how small is 0.3 microns compared to viruses? On average, coronavirus particles measure approximately 0.1 microns in diameter, so 3 times smaller than measured in our test. However, 0.3 microns is an important size to test, because 0.3 micron particles are the most difficult to capture.
The crazy reality is that particles smaller than 0.3 microns are actually easier to capture. Don’t believe us; believe the data. Here’s the science behind it »
Paper Towel Particle Capture
The results weren’t great. A single layer of kitchen paper captured just 23% particles. Adding an extra layer only increased particle capture to 33%.
For larger 2.5 micron particles, paper towel performed better. The single layer of kitchen paper captured 52% of these larger particles.
Update: new data on paper towel masks – we’ve published new data on the effectiveness of paper towels in our Ultimate Guide to DIY masks article. This uses a new and improved testing method, which shows paper towels are more effective than originally thought!
Learn more: The Ultimate Guide to DIY Face Mask Materials →
Do Paper Towel Masks Fit Tight?
One thing this test doesn’t cover is fit effectiveness–how leaky a DIY mask would be. Not surprisingly, masks that fit better will let fewer particles in. That’s one of the reasons why surgical masks score lower on fit tests than N95 masks.
Yet Studies Find Mask Leakage Has Small Effect on Flu Virus Transmission
Although surgical masks (and presumably DIY masks) are more leaky than N95 masks, randomized studies that have tracked infection rates have found that surgical masks are just as effective as N95 masks at preventing the transmission of viruses.
Researchers don’t know the exact reason for this. However, some scientists hypothesize that masks help, in part, because they prevent us from touching our face. That helps keeps us from “planting” viruses our mouth, nose, and eyes.
Bottom Line
Paper towel masks captured 23% of 0.3 micron particles, which is less than other DIY mask materials tested by researchers at Cambridge. However, if it is the only material you have, it is better than nothing.
WHAT NEXT?
Along with wearing masks, air purifiers with HEPA filters are also one of the best ways to stay safe from a variety of pollutants in our air including viruses and dangerous PM2.5. A recent CDC study confirmed significantly lower COVID-19 infection rates in schools that used HEPA air purifiers. HEPA filters can significantly lower the risk of a variety of deadly diseases including diabetes, heart disease, cancer, and high blood pressure.
Read More: Four Steps to Choosing the Best Air Purifier
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Not all paper towels are created equal. There are differences.
I beg to differ. I made paper towel masks with two coffee filters sandwiched in between and not only is it easy to breath through but it filters out more odors than the “non-medical masks” too like frying bacon or the smell of gasoline which tells me that its slightly more effective than the masks that are now widely available for general use.
Has any test done on tissue paper such as Kleenex tissue and etc.
Hi Phillip, Yeeeees, we final tried Kleenex since so many people brought that out. Here is the link with that article: https://smartairfilters.com/en/blog/best-diy-coronavirus-homemade-mask-material-covid/
I used Fluke 985 particle counters and tested few materials – coffee filters, cloth mask, cleanroom wipes, tissue, paper napkins (varying degree of quality). The high quality party napkin (the one you get from the dollar store for 20 ~ 25 counts per pack) has the best performance. For particles with size bigger than 2.5 um, it filters them out (the reading is 0). For particles with size of 0.3 micron, I could get > 80% filtration. It is not too shy compared to the surgical mask considering the availability of the materials. For the cloth mask, it is worse than the napkins (but not by much, still gives ~ 70%). So if your cloth mask is the cover (i.e. you can put a filter in), you can try using the napkins.
If you not sure what type of material you have all you have to do is make your mask and light a lighter in front of your mouth and try to blow , if it shut off isnt good material for a mask ( maybe try to-add layers if only choice) and if your lighter WONt shut off it will be very good fit material mask , I try it & its work …..not all kitchen towel not all t-shirt works the same as researcher claiming some t-shirt nylon or acrylic so the kitchen towel bed quality. Thanks
There are lots of different types of “dish towels” out there. Can you elaborate on the type of dish towel used? Was it terry cloth, smooth, waffle textured pattern, natural fiber, etc. I suspect that the a textured dish towel was used and that the textured pattern had played a role in the effectiveness but that is just my hypothesis.
Hi Melonie, Liz here. The testing dish towel we used is terry cloth!
Paper Towel even does not have the capacity to filter PM particles. Today World is goring through major Epidemic COVID-19. Proper N-95 is standard which fulfills all guidelines to protect virus infection….
Why not use an oridnary iron to kill bacteria and viruses and also refresh a respirator or home made mask.
Just dry iron the mask for a few seconds. Virus should be quite dead.
Hi Trisha. Song here. Yes, sanitizing mask in a high temperature environment should work. However, we do not have data on how long for a given high temperature would be enough or whether that may harm the filtration efficiency of the mask. It couldn’t be better if you can share some relating data-based cases.
Hey. The problem with surgical and other masks as far as protecting the wearer is that there are air leaks at the chin around the nose and near the ears where air comes in and doesn’t get filtered. A better fit will reduce that.
What about using grocery cloth from reusable bags made of polypropylene? Or what about the filtering quality of weed mats inside a cloth mask?
my 84 year old neighbor told me she lived in Italy during a large flu outbreak and they made masks from kitchen parchment paper. would this be a good filter?
I have been using a bandana with 4 To six layers of fabric and a double layer of blue shop towels as a mask, mainly to prevent me from touching my face but also to try to filter out any particles.. I am in the process of making actual DIY masks with 3 layers of linen, with the third layer forming a pocket for the shop towel “filter”. I doubt it Is as effective as a surgical mask but I’m hoping it is close, at least I don’t touch my face while wearing it.
Hello, Might you have any data or a way to calculate how effective a face mask can be if it’s made from a paper towel, plus 1 or even 2 layers of common tissues?
Filtration wise, with a single layer of tissue, tented over a paper towel and folded like a fan, you get 3 layers; with an additional tissue tented over a paper towel, you get 5 layers.
Here’s a little video I made showing how to easily make a simple, disposable mask with a paper towel, tissue(s), rubber bands and staples. It’s comfortable on the nose and cheeks because the tissues are soft on the face (ok, my fave is Puffs). And with the fan-folding technique shown, you get a nice little pocket fold so you can use your fingers to assist helping seal the mask around your nose and cheek bones for an effective fit. The paper towel portion ends up cupping the chin.
https://vimeo.com/402440416
As reports suggest, if it even just prevents people from touching their faces, that’s nice. Yet if it’s truly capable of blocking +/- 0.3 microns, or ?? that’d be terrific. And because the materials are so cheap, you’re more disposed to throw it away – efficiently, intensionally and carefully.
What about the effectiveness of 100% cotton woven cloth… quilter’s cotton?
Use of coffee filters as a filter slipped into a mask?
Hi Lissa, Liz here. We haven’t tested that yet. We know there’s a huge demand for reliable, science-backed data right now, so we’ve created a campaign to gather information on what our readers wants to test. To vote on what test you expect to see and support our campaign, visit our Fundly.com page here: https://fundly.com/best-diy-mask-materials
Hi Michael, we haven’t gather a complete testing data for using HEPA filter yet. But my guess is yes! Just to make sure your HEPA is a PP/PET material, not glass fiber. We are testings the specific filtration rate of HEPA now and will publish the result as soon as it comes out. Stay tuned!
Hi,
Have you tested blue ZEP Industrial Shop Towels? There might be a difference in filtering capacity between ZEP, Toolbox and Scott Shop towels.
I have the same question Can you please e mail any reply you may get regarding the safety of the Shop Towel
I”m wondering about Viva Paper Towel. It’s more like a microfiber than regular paper towels. Would that filter better? I hear that the blue Kimberly Clark cassette wrap that you use before autoclaving instruments is supposedly equivalent to N99. The stuff is pricey, but hospitals could be using it to improvise masks.
Hi Coleen, Liz here. Unfortunately, we don’t have data on Viva Paper towel yet. But there’s some good news — we know there’s a huge demand for reliable, science-backed data right now, so we’ve created a campaign to test 50+ more materials. To vote on what test you expect to see and support our campaign, visit our Fundly.com page here: https://fundly.com/best-diy-mask-materials
Hello one question. What if you use the paper towel as a filter INSIDE a homemade DIY cotton face mask? it is more effective?
Just a thought but if drying masks will kill Covid 19, and if drying masks at 40C will help kill Covid 19 faster and more effectively, how about drying your mask thoroughly with a hair dryer set on high? Seems to make sense to me and I would welcome any thoughts folks might have on this.
Hi Win, Liz here. Unfortunately, we don’t have data on that deactivation method yet. We know there’s a huge demand for reliable, science-backed data right now, so we’ve created a campaign to test 50+ more materials. To vote on what test you expect to see and support our campaign, visit our Fundly.com page here: https://fundly.com/best-diy-mask-materials
Hi Win,
That sounds like a dangerous idea because the hair dryer will blow particulars carrying the virus into air and other surfaces before being heated enough to kill the virus.
I suggest ironing, instead. It doesn’t spread particles and is at high temperature.
Hi Mariel and Marouane, Liz here! I’m not sure about if ironing would affect the filtration rate of the mask. But here is an article on how simply leaving the mask dry would disinfect the material: https://smartairfilters.com/en/blog/disinfect-clean-n95-mask-virus-coronavirus/
Hope this helps!
I have what I think is a great method to secure a paper towel to a face mask. Just finished fabrication of my first and want to share with others. I used two pieces of Bounty paper towels at the fold. Cut the towel to my needed size to attach to my mask. Now here is where things can be very, very easy especially for changing the filter paper.
I used 3/8” Seamstick which is a double sided sticky tape used by canvas shops to fabricate their products. See Sailrite.com. I cut and fit a length of Seamstick to the top edge of my paper filter. One side of the Seamstick is exposed to the glue. Next sewed the filter paper AND the Seamstick together to have one unit so I could pull off the protective paper tape later without pulling the filter from the mask. Now to attach the filter to the mask, simply remove the sewed paper tape that is part of the Seamstick product exposing a glued surface which you simply press against the mask. Now the filter paper remains in place and no need for any pockets for the filter.
When the filter needs changing, just pull off the old one and replace with another constructed the same way. Gees, really made things easier for me.
What about coffee filters..
Hi Joyce, we are testing coffee filters now! We know there’s a huge demand for reliable, science-backed data right now, so we’ve created a campaign to gather information on what our readers wants to test. You can support our campaign at our Fundly.com page here: https://fundly.com/best-diy-mask-materials
What about blue shop towels? There is a group out there that apparently tested them and they are supposed to be as good/better than surgical masks. Would love to know what your thoughts are.
Hi Jackie, we just got the shop towel and will test it as soon as possible! The result will be updated in our blog when it’s available! Stay tuned!
Thank you for this website. I am allready fighting 6 weeks against the misunderstanding that homemade or DIY masks won’t work, because this is our governments advise (and they stick to it, though even the WHO made a turn). And guess what? I recommended exactly to use the materials you tested the best and to copy the 3M 9332+ model that fits best. Now I can direct people right a way to your site, where things are explaned in a clear way. Thanks again!
I’m wondering what the effect would be if you have a “proper-fitting” DIY mask, AND include two layers of paper towels in a filter pocket…
Hi Charlie, Liz here. Unfortunately, we don’t have data on combined material yet. But there’s some good news — we know there’s a huge demand for reliable, science-backed data right now, so we’ve created a campaign to test 50+ more materials. To vote on what test you expect to see and support our campaign, visit our Fundly.com page here: https://fundly.com/best-diy-mask-materials
Has anyone considered using milk filter disks?
Being a paper towel is absorbent, would the moisture from your breath clog the material?
I want to make some facemasks, and I’m wondering if I should just use fabric liner or polypropylene lining. I’d appreciate a response, Even if it’s just a confirmation you’ve read this. I don’t want to make something that would give wearers false security, so I’d really like to know your opinion. I know you must be busy, and I learned alot from your website it’s just that I have time now to make masks and I just don’t know what’s the right thing to do. Thank you. I don’t know where else to go.
Hi Laura, sorry about the late reply. We’ve got thousands of comments now… Did you check out our latest DIY material article, we’ve tested more materials and polypropylene is in the list too! Here is the link:https://smartairfilters.com/en/blog/best-diy-coronavirus-homemade-mask-material-covid/
What a great read! How about a layer or two of Kleenex or other tissue paper instead of the coffee filter? After all, Kleenex was originally created as a filter for gas masks in WWI.
Hi Steve, Liz here! we haven’t tested combined material yet. We know there’s a huge demand for reliable, science-backed data right now, so we’ve created a campaign to gather information on what our readers wants to test. To vote on what test you expect to see and support our campaign, visit our Fundly.com page here: https://fundly.com/best-diy-mask-materials
Ive seen studies showing blue shop paper towels are very effective. One study showed using 2 folded inside a cotton diy mask blocked 90% of the particles. Have you tested these yet?
Hi Heather, we haven’t tested the blue shop paper towels yet. We know there’s a huge demand for reliable, science-backed data right now, so we’ve created a campaign to gather information on what our readers wants to test. To vote on what test you expect to see and support our campaign, visit our Fundly.com page here: https://fundly.com/best-diy-mask-materials
I have a pillow topper with a lining made of 100% polypropylene. I read in the WSJ that polypropylene is in high demand for making n95 masks. Do you think lining my DIY cotton mask with my pillow top lining is s good idea?
Hi Laura, we haven’t tested 100% polypropylene yet. We know there’s a huge demand for reliable, science-backed data right now, so we’ve created a campaign to gather information on what our readers wants to test. To vote on what test you expect to see and support our campaign, visit our Fundly.com page here: https://fundly.com/best-diy-mask-materials
Hi, these are great insights you are producing! I’m wondering about another material particularly in use in different African countries: Wax Cotton/Fabric?
I tried paper towels as a filter. Unfortunately I could barely breathe and took out the paper towels within minutes. Breathability is a huge factor in keeping the mask on.
Can you use an air conditioner HEPA filter as a filter in a DIY mask?
Hi Michael. Song here. We have posted another article on this: https://smartairfilters.com/en/blog/hepa-filters-make-diy-face-masks-covid-coronavirus/
How about putting a kitchen paper inside the DIY cotton mask? Will it be better?
Hi Pearl, We haven’t tested combined material yet. We know there’s a huge demand for reliable, science-backed data right now, so we’ve created a campaign to gather information on what our readers wants to test. To vote on what test you expect to see and support our campaign, visit our Fundly.com page here: https://fundly.com/best-diy-mask-materials
Thank you so much for what you’re doing!
Can I please ask your opinion on a few more things used for masks?
1) Masks out of bandage.
Layered bandage, I’ve seen up to 12 layers, though can be 2-4.
Or bandage with cotton wool in between (usually about 1cm).
2) Masks (medical or DIY) soaked in water with salt, or with salt and soap.
It’s supposed to disinfect, but also makes the cloth rigid, with visible crystals.
So I was wondering if that might change virus catching too.
https://www.nature.com/articles/srep39956?fbclid=IwAR1dJ8vXES-ZNwR3dALqKtHJlJAuBLZflqowOctiux17EzVeVROqO9ii_XA
Thank you!
Hi Yia. Song here.
Multi-layered bandage may not gain good breatheability. Besides, here is a simple but effective way to disinfect masks, just to leave them out to dry.. And here is why you shouldn’t wash masks.
Greetings ! Great article!
One question , what if i use three to four Layers of paper towels?
We didn’t test more than 2 layers of paper towel, Kev. The reason being was I found it too hard to breathe through any more than 2 layers! Increasing the layers may see a small increment in filtration efficiency, but I wouldn’t expect doubling the layers again (from 2 to 4 layers) would double the filtration efficiency. And you almost certainly wouldn’t be able to breathe through it!
Paddy, Could you add a #4 coffee filter (single layer) behind the paper towel?
Hi Laura, coffee filter is on our to test list already! We’ll publish the result when it’s out! Stay tuned!
Please test coffee filters — the cylindrical type used for mini- or large-sized urns’ baskets. The US Government’s Centers for Disease Control (CDC) recommends spreading one open and inserting it behind the cloth when sewing a home-made mask.
Hi Paddy and Team,
Thank you for sharing your findings. I found your articles to be very helpful as we’ve been testing different materials for a DIY mask (this article on DIY mask materials in particular: https://smartairfilters.com/en/blog/best-materials-make-diy-face-mask-virus/?rel=1).
We have designed a DIY mask made from printer / heavy stock paper with a cutout for different filters and have found it to be comfortable from a fit and breathability standpoint. So far we’ve found the vacuum filter to be the most effective and have tried paper towels, napkins and coffee filters (we look forward to your shared findings). Though a tea towel may be too heavy in this application, we’ll consider trying lighter fabrics like poly-cotton.
If anyone is interested in trying our mask design, we’ve made it available to download for free at http://www.freecovidmask.com. Would love to hear your thoughts / ideas on any other household materials we should consider for the filter, or even the efficacy of the printer paper itself.
What about 2 pcs of paper tissues (3ply each)? I put video on YouTube how to make it https://www.youtube.com/watch?v=EzS-522CeZQ
What you’re missing is that airborne CV is probably not the 1 micron virus particles themselves, but rather sneeze droplets of water carrying the virus that would be quite a bit larger Absorbent paper towels may do very well at trapping such particles. I’d like to see the results of such a test.
I heard construction paper towels are real good. Those are the blue paper towels sold at building supply stores.
Hi, I wanted to follow up on a post I left some time ago (can’t find it now). I’m making masks from a material that is similar to kitchen paper towels, except it’s more industrial grade. Comes in a roll without perforations. 4 ply with a nylon scrim for strength. The material is very tough and doesn’t fall apart easily even if wet. In this prototype I’ve used two layers of it and I’m using a thin copper wire over the bridge of the nose to easily achieve a tight fit. The material is available under a variety of brand names but seems to be widely used in industrial settings as well as hospitals, for cleaning of course.
The masks take me about 3 minutes to assemble and here in the U.S. the cost is between $0.07 to $0.10 depending on the elastic band. As you can see in the link below I use a double layer. The tight fit means the mask inflates and deflates slightly with each breadth. Breathing is not forced.
I’d love to send you a few complete masks for evaluation, do you think that would be possible?
https://www.flickr.com/photos/28906010@N06/albums/72157713649874836
I just looked at your design and videos. Looks good and quick! I would like to see the test results using your materials.
I read the article about paper towels not being very effective. I wonder about the bamboo reusable paper towels? They appear to be substantially thicker/denser.
I would like to know the answer to this question too. I have some rolls of Bambooee Un-paper towels. They can be washed up to 100 times each. I was wondering if they would work as a filter in homemade face masks.
Great article! I have the same question here…I have a pack of Viro Bamboo reusable towels. 🙂
A good rule of thumb is to hold it to the light and see how much light passes through. If you can see a lot of light between the fibers, it’s not going to be very effective.
I’ve been using the bamboo reusable toweling. Can’t find any data but its non-woven, thick and a bit difficult to breath through so i’m hoping it is effective. I use “tin ties” (the double wire closures like on coffee bags )on the nose, sew directly onto the bamboo towels. Then a layer of fabric on each side.
I assume nothing with these masks or any mask and always keep 6 ft distance.
Hi, anyone done any research that 100% natural cotton batting (used for quilting) is effective as a filter in mask?
I saw a video regarding using different Pellon type products. The batting was super hot to wear. The non-woven interfacing, sew-in or fusible worked wonderfully and was supposed to be able to filter out the tiniest size particles. If you look at how the M95 masks are made, it looks like they are using layers of items like non-woven interfacing. Again, the batting was too hot on the face.
Or crafting felt?
I made masks from a tea towel and used a layer of allergy mattress protector inside – just because it was all I had
Would the cotton from sheets work as well as pillowcases?
Hi Lizzie, Liz here! We’ve tested cotton sheet later in another article, see here to check it out: https://smartairfilters.com/en/blog/best-diy-coronavirus-homemade-mask-material-covid/
Thank you Paddy and Smart Air for posting this valuable content. Your other article about DIY masks made from various household materials based on the Caimbridge study talks about breathability, my own anecdotal test just found doubling a paper towel did not significantly affect breathability and while as you point out the gains are modest, it is better than nothing. Worth nothing though, I did not try to wear it for three hours.
The effectiveness of paper towel is at 22% at 0.3 micron from your test, much lower than a similar study conducted by Dr. K Kwong for the “HKMask” http://diymask.site/, which stated ~70% efficiency. Obviously these are two separate tests with different test setup and variables. The brand they use is “Vinda”. Do you have any thoughts on this? I live in the US and I am unfamiliar with these brands. Would the “Bounce” brand paper towel be comparable to the one you tested with? I’m hopeful that some paper towels are much more effective than others. It may help if you can add the brand you use as a reference. Even better, maybe repeat the test comparing different brands and thickness? I’m trying to help a local hospital system collect more masks. I want to find a safe solution. Thanks!
Hi, Becca, Liz here. We’ve tested another 30 materials after the initial article on DIY mask materials and the paper towel article. Check it out here and hope this helps: https://smartairfilters.com/en/blog/best-diy-coronavirus-homemade-mask-material-covid/
so why not make a cotton mask with an open that fits well and place paper towels inside for added filtration.
why wouldn’t that work.
That is absolutely possible and the idea of this type of mask by a doctor from Hong Kong. See here for more infromation about filtration efficiency as well as tutorials on how to make these: https://diymask.site/
That is what I have done for my family.
I made mine out of 2 layers of cotton, then when I go into a store or if around other people I take one choose a size scott paper towel I fold it into thirds and just place that inside my mask. My mask fits snugly around my face, nose and chin: I do have mild emphysema and breathing is no harder with this than without it.
I made my mask with a tshirt cotton fabric and I use double paper towel inside of it just for extra protection. If the cotton mask itself captures 50 % as it says in the article and the double paper towel mask about 30% then my mask should capture about 80%???? Or is it different when combined?
I used coffee filters, inside my homemade masks.! Also, because that is all I really had at the time? Don’t know how well it will actually do, but it is better then nothing? I was wondering about cheesecloth too?
Haw shower curtain fabric will be effective.
How about folding two coffee filters in half and attaching with surgical tape please test and if it works get the word out
Hey Mike, we’re working on testing coffee filters and should have a follow-up article out soon!
That’s what I have been using inside my homemade masks, two folded in half. Was wondering how effective this is though?
Did you try ordinary paper coffee filters?
We’re working on testing coffee filters and should have a follow-up article out soon!
I saw a video where HCWs were using coffee filters, a size 2 (smaller) inside a size 4 cone filter. . They are readily available and were being produced with materials on hand to create ties, wire for nose edge taped on, etc. They were able to get a good fit, and showed how the mask hugged the face and moved in and out a bit when the wearer breathed.
Have you tested this material, 1 or 2 layers, for particle capture?
We’re working on testing coffee filters and should have a follow-up article out soon!
What about Terry cloth towels? My husband thinks those are dishtowels so that is what he bought
Hi Karen, Liz here. Unfortunately, we don’t have data on that material yet. But there’s some good news — we know there’s a huge demand for reliable, science-backed data right now, so we’ve created a campaign to test 50+ more materials. To vote on which materials we should test and support our campaign, visit our Fundly.com page here: https://fundly.com/best-diy-mask-materials
2 #4 coffee filters, doubled. Place a piece of polypropylene between them at the pointed area, mouth and nose. Staple a 12” x 1/4” elastic piece at both sides to hold in place.
Takes seconds to make each one.
Has anyone tested coffee filter paper for effectiveness?
Here’s a video on making a mask from coffee filters:
https://www.wwlp.com/news/health/coronavirus/web-extra-how-to-make-a-homemade-face-mask/
Can we use double coffee filters as masks
Was just wondering about that myself! I would think coffee filters would be way better than paper towels. Also, what about air filters like the ones used for fans and furnaces that purport removing 99% of airborne junk?
Would putting a couple of paper towel layers over the air registers in our home be effective in reducing potential transmission through the furnace? Asking in case we have a sick neighbour downstairs in a shared house.
Hi Trent, we haven’t done any test on attaching the paper towel on the furnace. My guess is if you make the it multiple layers and well sealed, it can help. But I don’t know HOW helpful that will be.
You’re going to kill your furnace though. Some of those registers will be for air return. I learned that the hard way when my kid went to college and I shut down the registers in rooms we no longer used.
I think the thing to consider is that the furnace is designed with a certain air flow which captures the heat form a heat-exchanger. Limiting the air flow by 50% or more is a huge departure from the design specs which may have a dangerous results such as overheating or a fire. Some units will tone down the heat input to reach the correct air temps at the furnace output but you would have to contact the manufacturer to check if that is the behaviour of your unit. In either case limiting the air flow will cut down how much heat will be pumped into your home so you will be colder too.
Just saying…. The best outcome would be to get a proper air filter element from a furnace that has one and adapt it. It will have high air flow rating and surely would be better at filtering than a paper filter.
Have to make sure that it doesn’t increase pressure so much that the commercial filter pulls away from its surroundings & so stops nothing.
Also up to a point a dirty air filter filters better than a clean one because the deposited dust also forms a filter
Paper towel would interfere with the air flow too much. Better to replace your furnace filters with new pleated screen type filters.
Hi Trent, It would be more helpful to put AC filters on the external part of your ducts/vents and sealing it up with sealing tape that does not let a lot of air escape. just note the micron value of your filter as the virus is, this is what I have read, 0.1 to 0.4 microns.
Also, there is some speculation that the heat might hinder the virus, lets hope that is true.
Finally, what you can do is put out little caps full of rubbing alcohol in front of the vents (not inside!! remember it is flammable at certain temperatures), the evaporating alcohol will disinfect the air.
Again, these are just preventative measure, they are not a cure.
I wish you the best of health.
Hi Paddy,
I would like your opinion on the following solution:
Use the T-shirt/pillow case cotton as you recommend, get a sewing machine, and make an envelope/pocket in the shape of a surgical mask. Inside the pocket their could be (any) replaceable filter fabric, such as a better-quality folded paper towel. The opening/sleeve of the pocket probably needs to be on the inside (mouth side) of the mask and it will look a bit like the opening of a pillow case (overlapping fabric).
The mask should have some proper rubber bands or strings, isolated copper wire sewed in a seam (nose support), and maybe be further tailored with some folds to get a more facial shape.
After using the mask a couple of hours, take off, take out the paper filter, wash/dry properly, insert new filter, use again.
It will not be the easiest mask to make, but if we can call an army of sewing machine volunteers, we can build a sustainable mask supply.
Given the resistance of paper towel to breathing (Paddy says noticable resistance to a double layer) I suspect that what you would do is breath more through the cracks around the edges of the mask.
Hi, I decided to try masks made by industrial strength paper towels. They are very heavy and the description is as follows:
4-ply for extra-absorbency, plus nylon reinforcement to resist tearing (prism scrim reinforced). Low-linting. Link here: https://www.homedepot.com/p/HOSPECO-Prism-Scrim-4-Ply-Blue-Reinforced-Wipers-6-Rolls-Carton-HOSC2375BH/303867204
Since these are 4 ply and have scrim reinforcement I’m guessing they will work better than a good 2-ply common paper towel. What’s your opinion?
Hi Carlos, theoretically yes, the double layer of the 4 ply will work better than double layer the 2 ply. But we have never tested that paper towel. My guess is based on double fold cotton and double layer the regular paper towel can both increase the filtration rate.
Has anyone tried the cloth-like paper towers? I bought some at Walmart & was thinking of trying them.
Hi Ruby, do you mean like the industrial cleaning paper/cloth
I read a discussion that a paper towel, which has been made wet then left to dry is better as a filter – and then inserted inside a 2 layer fabric mask.
Ultimately anything is better than nothing, and will help if you’have’ to be around group of people.
You know that kind of makes sense and I wonder if it’s because once it’s wet the fibers tend to blend together better?
On the other hand, washing a mask decreases it’s effectiveness. Could be that fibers that used to stick out from the rest now clump like wet hair.
I went into a website teaching how to make face mask and there is an insert pocket for electrostatic filter which I think is often used in airconditioning units and this is washable. I bought a few pieces and cut them to fit into the face mask. How effective are these electrostatic filters? I thought this would be great as both the mask and the filters are washable and reuseable.
Hi Petrina, I guess the electrostatic filters means materials people use for N95 masks, you can read this article for more details (there is also an video) on how the filter works: https://smartairfilters.com/en/blog/wash-n95-mask-effective-virus/
What about the use of eye drapes as raw material of mask? I want to know it’s filtration capability.
Hi Siddhartha, I did a brief search on eye drapes, I saw they are made of a material called SMS or spunbond meltblown spunbond. It is also one of the materials people will use to manufacture surgical masks. But I didn’t see any filtration rate of the general SMS material. The quickest way to figure it out should be to contact the eye drape manufacturer for this information.
Dear Paddy Robertson,
I’m curious if you made any experiment with tea-bag material. I made a normal anti-dust mask with an application of carbon filter surrounded by an emptied tea-bag, and it seems to be good, but of course, I have no infection (now). What do think about tea-bag, and carbon filter? Thank you your answer.
Sincerely
Laszlo Katona (Hungary, Europe)
Hi Laszlo, I haven’t been able to test tea-bag material yet, however my understanding is that the fibers in a tea bag are not that fine or close knitted, so it may not be that effective at filtering out the viruses. But let’s wait for the data. We will try to test it soon!
What about coffee filter paper?
We’re yet to test coffee filter paper, but hope to get round to it soon!
What about using a honeywell elite allergy air filter fpr 10? I bought 2 thinking that if worse came to worse I could cut it up and turn into a mask. I know the fit would not be perfect but would it be better than nothing if i have to take care of a sick family member?
It has a thin metal wire weaved into it which may make it slightly moldable to the face. I haven’t tried yet. Thoughts?
Hi Louisr, we haven’t done any test on inserting a fabric to a DIY mask yet. But I’d say since paper towel and cotton both works on partially filtering out the virus, it is always better to have a mask, even if it’s not well fitted, covering your face than nothing.
Coffee filter is like 20 microns and not consist. Would help with dust.
5 layers of coffee filters…