Which air purifiers are best for reducing microbial and smoke particles from room air?

Thank you for this very informative and helpful article. I was interested in purchasing the Coway Airmega ProX or the Blueair Blue Pure 211i Max but seeing the prices jump 30% & 40% respectively since last month steered me in the direction of the Winix 9800. I realized after making the purchase directly through Winix that this article says that the Winix 9800 can remove 99.97% of airborne particles 0.1 microns or larger whereas the Winix website states the following: ''Winix True HEPA Captures 99.99%* of airborne allergens including pollen, dust, smoke, pet dander, and other ultrafine particles as small as 0.003 microns,'' which is even better than I originally thought. Thanks!

The problem with the Conway bad smelling filters seems to be ongoing with Conway based on Amazon customer reviews.

In March of 2024 I bought a Coway air filter directly from Coway. It made a terrible chemical smell that filled the whole room and sent the whole family fleeing.

When I contacted Coway and asked to return it (their website says you can), Coway insisted that this smell was impossible and that at most it could only ever make a very mild smell, and we were being oversensitive to complain about it. It took a ton of back-and-forth messaging with them explaining that yes it really did have THAT bad a smell, to get them to take it back. They finally did take it back, but they subtracted a bunch of money for shipping costs, when I think they should have been responsible for the shipping costs, since the smelly unit was their error.

Based on this experience, I would NOT buy a Coway product again.

Some great alternatives to DIY air filters made with box fans, are the ones created using PC fans. Their CADRs are similar to, or better than the DIY Corsi-Rosenthal boxes, and commercially-produced air purifiers. They also use minimal power, and produce far less noise. They are, however, more complicated to build, if you are starting from scratch. DIY kits, in which the components are ready to assemble (with filters you buy yourself), can be purchased from Clean Air Kits.

What about the Winix C545 WI-FI? You haven' rated it.

We have four of the Winix 5300-2 and have run them 24/7 on Speed 3 (very quiet) since the start of COVID. They were selected primarily on the basis of a rating in Consumer Reports, which included the fact they were quieter than most. Our experience with them has been excellent and I highly recommend using the optional Type U pre-filter for pet dander and dust, to extend the life of their two standard filters, charcoal and HEPA. Ballpark 5300-2 price is $150 and filters are not as expensive as some brands. I have no financial interest in Winix and am simply a curious geek who's also a retired Professional Engineer - QA Manager.

We just purchased a Blue Pure 311 Auto ($249.99, purchased directly from blueair.com). This is our first air purifier. Has anyone had experience with this model?

Do you recommend using a car air filter to improve the air inside a car?

Please advise.
Some larger Germ Guardian air purifiers state that they include a UV-C light (that) helps reduce airborne bacteria, viruses, mold spores* and works with Titanium Dioxide to reduce volatile organic compounds (VOCs).
However, Consumer Reports cautions that with regard to Photocatalytic oxidation (PCO): Some air purifiers use ultraviolet radiation and a photocatalyst, such as titanium dioxide, to produce hydroxyl radicals that oxidize gaseous pollutants. Depending on the pollutant, this reaction can generate harmful byproducts, such as ozone, formaldehyde, nitrogen dioxide, and rbon monoxide." 
Is this a possible issue with Germ Guardian models such as the Germ Guardian AC9200WCA?

I avoid buying air purifier that do not utitize (and sell) PRE-filters separately from their HEPA filters, because the pre-filters easily accumulate dirt and dust and need to be replaced more frequently for maximum efficiency of the HEPA filter. ( I much prefer replacement of the inexpensive pre-filters, rather than messy vacuuming when trying to clean them)T he often dirt-covered & unsightly pre-filters should not be exposed (or wrap around) the purifier, and instead need a guard or grill cover (which also protects the of pre-filter from inquisitive children’s hands and from being easily damaged). “All-in-one” filters are an expensive & impractical deal breaker for me. Also, I avoid cylindrical shaped purifiers with air inflow on al sides because that limits their placement along walls by cutting down inflow efficiency on one side. Direction of output air flow is also important, unless you enjoy being in a constant draft. As for noise, use in a bedroom provides a soothing white noise background. Not a problem \-for me.

I just ordered one of the Nuwave oxygen pure zero air filters. I pretty much figured based on your note of the Nuwave above that it would not cover the space they advertise. I was getting it for my bedroom so that did not matter. Your paragraph mention the filter cost replacement though. The Nuwave filters do not need to be replaced. They are all washable which is why I got it.

Being that harmful wildfire smoke particles are 2.5 microns in size, is there any potential health-related benefit to choose an air purifier that is rated as removing smaller particles that are .1 microns (or larger) versus those rated as removing particles 3 micron (or larger)?

Very thorough review of an apparently very complicated topic. Thank you!
Could you possibly address air cleaners that are installed to work with whole house HVAC (forced air) duct systems? I have Trane Clean Effects on both my systems (one in attic, one in basement), but I'm not sure they do much. I'm interested in improving things a bit. Also recently put an adjustable size FRP 4 Filter in a return (the only place in the system where you can do that). Just found that Airpura makes something that can work with HVAC and will try to look into that some more. Thank you!

We lived in the inland northwest for 10 years. Summer wildfire smoke was a problem but I found buying carbon air filters for my HVAC and changing them weekly during the smoke events worked great including the time our air quality index reach 550 for 3 days. You couldn't see to the end of the block and going outside for any reason was not recommended but my air quality inside was great.

I live two blocks away from a major highway. Please advise me as to the best air purifier for exhaust/ozone/benzene, etc., emissions.

Just purchased the Coway Airmega 300. Picked it because of the low noise level and am happy so far. I saw that the replacement HEPA filter was mentioned by CL as a $99 annual cost and was concerned because the unit has two of these filters. However, Coway sells a 2-pack for $99, so that is an accurate figure.

I understand the Blueair purifiers have passed all sorts of tests and are critically acclaimed. However it's worth mentioning a large number of owners have reported a toxic chemical smell that either burns away in a week or never burns away at all. I'm one of those owners that experienced this.

I think I might be missing where you give a standardized ceiling height. 2 dimensions don’t provide a complete room size.

Would help to have recommendations about humidification. Thanks

Regarding "If you are already using an air purifier that is appropriate based on room size (i.e., it cleans the air volume at least five times per hour), adding another air purifier is probably not necessary. " Probably not for many people, but...
With 3 months of Pacific Northwest wildfire smoke this year and now 5 months of wood heating by many neighbors, in my large rather leaky 1970's home I often find it necessary to use more than one air purifier in a room to mantain the particulate count on my Dylos DC1700 at a healthy level. I have three purifiers ($200 Honeywell, nothing fancy) on dollys and can easily roll them from room to room. An advantage of more than one is that while using the Dylos for measuring, two purifiers set to Medium is more effective than one on High, and the sound is much easier to sleep through. An increase in electricity? Sure, but it is hard to put a price on breathing freely.

I recently purchased two Shark HE405 air purifiers from Sam's Club. I put the first one in the master bedroom and quickly noticed a difference in the air quality. I felt I could breathe easier. I have the second one in an open area near my office space. I think the two together have improved the air quality in my house. (I have no financial interest in this company.)

I would be interested in a review of Shark air purifiers.

Did you ever come across Aeris Health purifiers? Its made in Swtizerland, no ozone and they offer consumer and medical grade purifiers.

We are severely disappointed in our BLueair 211+. We've stopped using it because the filters offgasses some plastic like chemical smell that pervades the whole room. We ordered a replacement filter and it stunk even worse! NOT recommend!

Bought 3 Austin Air purifiers several months ago to replace older Blue Air 211+ models. The filters for Blue Air purifiers have become extremely expensive. Boy have I been sorry I swapped the Blue Air out for Austin Air models. First, two of the 3 Austin Air models had fans that began to heat up with continued use at low speeds. I have to the say the Austin Air folks were great about replacing them quickly. However, here it is in the middle of July and fire season is at its all time high and for the first time in almost 5 years, I have smoke in the my house. Blue Air models kept even the heaviest California smoke out. Smoke is light today, but making my eyes burn in my house. I bought the Austin Air models that covered smoke particles as well as to meet bio needs and chose them even though very pricey because the filters were warranted for 5 years with graduated use discounts. So sad. These units are very expensive and really do not work well and are very loud even on lowest speed. I did not mind the noise if the smoke was kept away, but alas now have both smoke and loud noise. Smoke particles are larger than COVID particles, and if the smoke is not being filtered out, pretty sure smaller particles are not either. I have no financial interest in either company -- Austin Air or Blue Air.

My WINX has been a big disappointment. The first year I would see dog hair and dust on the washable and even charcoal filters. It was obviously working! I got new charcoal filters, but the hepa looked completely clean, no discoloration at all. Now 3 years later, nothing. New filters, nothing, dust or dog hair shows at all. I can't tell if the hepa needs to be replaced since it looks pristine. My Honeywell grabs every hair, dust mites, and I can see the dust on the charcoal filter big time. It's over 7 years old. I don't even see Honeywell listed here.

Can you review the LG line of air purifiers? They claim to be the best.

Does low humidity in winter effect rates ot Covid 19 infection ...say humidity 20s vs summer 50s ? If so would humidifiers to add more water to winter air be useful? We r in SW FL.

Isn’t cubic square feet relevant to capacity? The open part of my apartment is 700 sq ft, with 11 ft ceilings. Without a discussion of total volume, not just square feet, I’m reluctant to buy anything. It seems like I would need two large machines.
It would be very helpful if you would address this issue, which is even more significant for people with large, open houses.

Can you please review the Idylis 3-Speed 310-sq ft HEPA Air Purifier? I bought mine at Lowe's about 10 years ago. I want to know if it is a good air purifier or, if I need to replace it with one of your recommendations. Thank you SO very much!

Will you review Hatha Space Medical Grade portable room air purifier?
Thanks

Have you looked at the SilverOnyx air purifier? I'm using 3 of them in my store, and they seem to work very well against mold, etc. Price is good, and each purifier covers about 500 SF. Very easy to use, clean, and replace filters (I try to clean the filter cartridge monthly and replace them yearly.

Have tried two of the Blue Air filters. They both gave off very offensive odors that the company said was from glue used to hold the filter together. I returned both. I did not see any comments about odor on the CL evaluation of this unit, but there are many similar complaints on many other websites to include Amazon.These are made in China. I replaced them with the Austin Healthmate. There is no odor at all and they are doing a great job. They are constructed on parts made in the USA and are manufactured in the USA. I believe USA made is probably a better choice during this time and maybe our USA made are better all of the time. I have no financial interest in either of these companies. I just want clean air in my home without any possibility of toxic contamination.

I purchased several Winex air filters of the model you reviewed at Costco for $99 ($30 off of their regular price). I notice they are out of stock today but this seldom lasts long. I am pleased with these filters. They are quiet, efficient, and the replacement filters last much longer than I expected.

Can you review the NUWave Oxypure that is heavily advertised on TV ?

What is your opinion on the Austin Air Filters?

Can you review the Amway Sky Atmosphere Air Purifier?

What are your thoughts on the VEVA 8000 Elite Pro Series Air Purifier?

How can I clean an air purifier's filter without exposing myself to the virus particles caught in the filter? thanks.

Hi Can you research this please?
I have had a Rowenta Intense Pure Air filter for 5 years. Nano captur technology. It has a pre filter, an active carbon filter, a true hepa filter and a nanocaptur filter. I order filters from Amazon.

I'd like to see a review of Aireox. The owner built this machine because his wife has MCS as do I. I find it gets rid of chemical odors very well, not sure about dust

I purchased 2 Honeywell air purifiers this year twice through Amazon. Based Consumer Reports, for me, Honeywell had the best noise & price affordability. However, exchanged the first one thinking there was something wrong it was so noisy?so purchased another which had electrical problems after the first week and stopped working . Conclusion thank God I had 30 days to find out I would’ve been stuck with a broken device , that was only quiet when it was on low:However there’s so little airflow on low and the 4 Hepa Air filters were as pristine despite supposedly cleaning the air for weeks ..I wish I could recommend them but I absolutely don’t.. so gratefulconsumerlab.com reviewed .. Will let you know what happens

Do you have plans to test Air Oasis?

I have Austin Air machines for over 15 years. They are pricey up front, but made of steel, not plastic, so no off-gassing. Their filters last years. Curious why they aren't mentioned here? During CA fires 2 years ago, someone left open the kitchen window over night while at Lake Tahoe. I came downstairs and it was like the fire was in the house. I closed the window, ran the machine for an hour, came back downstairs and no smell. They do not have all the bells and whistles, and are slightly loud even on the lowest mode, but IMHO do a great job. I have no financial interest in this company.

I just bought the BlueAir 211 and like it, though it's hard to move. No handle, you have to lift from bottom. It has removed smoke from wildfires here in Colorado. AND I would recommend the Honeywell. I have an old Honeywell 20 years now and still working great. I would of bought another Honeywell but it's unavailable and thought I would try the BlueAir. Thanks for these reviews.

What do you think about Winix C535 and similar models?

Also wondering if there is anything cost effective for a bathroom.

During wildfire season in the West, clean outdoor air is hard to come by. I am more interested in air purifiers that clean smoke particles...

Thank you for this article. As a psychologist who sees some clients in office, I am very interested in this kind of data. A purifier that a lot of my colleagues use and recommend is the Air Doctor. I have ordered two but they gave not arrived yet. I do not know its actual efficacy in practice and I'd be curious how it would fare in a review like this. Disclaimer as per your guidelines: I do not have any financial investment in the Air Doctor.

A local health practitioner uses the Medify MA-25 W1 air filter. Is that a recommended air filter for consumers? Also, is the HoMedics TotalClean 4-in-1 air purifier recommended?

We have Winix and Theropure air purifiers. Have you ever evaluated those brands. We'd like to know before we purchase another, of either one. Thanks.

What do you think about the : Coway AP-1512HH Mighty Air Purifier with True HEPA and Eco Mode

After the horrendous smoke of the past week we are considering a whole house air purifier that is connected to our heating/cooling system. Would love a review of these options. As we all evolve to deal with climate change, these will become more of a standard feature of most homes, I imagine.

Nice summary article on indoor air safety. Most indoor forced air heating and air conditioning systems currently in use are not built to handle filters rated finer (higher) then a MERV 11. My service technician recommended last year that I add a RGF's Reme Halo UV light device to my furnace. Luckily for me, I agreed and did this before prices doubled this year. I may still add portable air cleaners upstairs and downstairs.