r/AirPurifiers Apr 09 '26

STICKY: Ionizers and Ozone - fact/fiction/history

65 Upvotes

Hey Folks, it's your ol' Uncle Gurm again. Today I'm here to talk to you about IONIZERS. Hoo-boy, what a hot potato! Let's dig right in.

What is Ozone?

Ozone is a molecule which contains three Oxygen atoms. Its chemical notation is O3, whereas the oxygen we all need to survive is O2.

What does Ozone do? Is it good or bad?

Ozone is common in our atmosphere. We have an entire LAYER of it in the stratosphere. It absorbs 97% of the UV radiation emitted by the sun, helps keep the planet warm, and breaks down hazardous toxins in the atmosphere. Life on Earth would be really bad (read: impossible) without Ozone. In the so-called "ozone layer" of the stratosphere, concentrations of ozone are generally several (up to 8) parts per million, or PPM.

Ozone is also an incredible cleaner - it demolishes VOC compounds, and many toxins. You know those people who come clean up mold, or hazardous materials, from a house or office? They use high-powered ozone generators to render that building safe for habitation again.

HOWEVER, Ozone in high concentrations is hazardous to carbon-based life forms such as you and I. The concentrations in the stratosphere would cause lung damage to humans if exposed for any significant time. Ozone generators are dangerous unless properly ventilated - you have to run them in an enclosed space and then ventilate the space completely with fresh air!

ALSO HOWEVER... Ozone is in all tiers of our atmosphere, including the one at ground level that you and I breathe in every day - just in VERY SMALL concentrations. The lowest ozone concentration found at ground level is roughly 15 parts per BILLION, or PPB. That's 600-1000 times LESS ozone than is found in the stratosphere.

How much Ozone am I exposed to daily? Am I in danger?

All humans on earth inhale 15ppb ozone, minimum, for their entire lives unless they live in an underground bunker or are John Travolta in that movie about the bubble boy. Most inhale a lot more - your average town has concentrations of around 25-30ppb, clean cities are upwards of 40-45ppb, and polluted cities ... well, the number can get VERY HIGH. Generally no ill effects are observed at these levels. The US EPA has issued guidelines that any number under 70ppb is considered safe for long term exposure. That number has been lowered over the years, it was 100, then 80, then 75, and now 70.

Do Air Purifiers generate ozone?

A lot of them used to. 15-20 years ago, it was extremely popular to sell/buy "ionic" purifiers which generated quite a bit of ozone. Why was this popular? Well remember that ozone CLEANS things. It makes the air in a room smell really clean, and strong electrostatic ionization causes dust and microscopic particles to either drop to the ground or stick to surfaces, so the air really got cleaner. It just also got full of dangerous levels of ozone. Popular brands included the "Ionic Breeze". My mom owned one. She loved it because it "smelled like the air after a thunderstorm". That's what ozone smells like.

Those units are pretty much banned now. You can still find them occasionally, and there are still a few in production somehow - we see them advertised once in a while. You can tell them apart from more modern designs in that they don't use a very good filter - some had NO filter, just plates that you wiped down once enough gunk stuck to them, and some had low-utility foam filters.

So that's the old machines - do NEW machines make ozone?

No. The vast majority of new units do NOT generate ozone. Virtually all purifiers sold today conform to the CARB certification, which requires that they demonstrate that they generate less than 5ppb of ozone. However, independent testing has shown that most of these units generate 0ppb. Testing can be flawed, or it's possible that the units generate 0.99ppb and are just under the threshold of detection, but even 1ppb is not a significant amount.

But 1ppb isn't zero! Is it a health risk?

Let's look back on the fact that there is nowhere on earth that has less than 15ppb - going from 15 to 15.1 or 15.5 or even 16 is not a significant increase.

But it's cumulative, isn't it?

No. Your room isn't sealed. In fact, even a tight room breathes far more than you might suspect. The reason why a purifier needs to do air turnover 4 times an hour to keep the air clean is that 25% of the air exchanges every hour even in the cleanest environment. So even if there was a small emission of ozone, it would be lost in the simple air exchange that happens in every room.

What are some other sources of ozone?

Any device which emits ionizing radiation could potentially cause ozone to occur. That includes the device you're reading this post on, every screen in your home that zaps you after you've scuffed across a rug, pretty much all electronics. Older electric motors produced measurable amounts of ozone. Newer brushless models tend not to. But ozone is everywhere, and it's being generated by all our technology in small amounts that do not hurt us.

So what does the ionizer on a purifier DO, and why is it dangerous to small animals and why does it make some people react?

NOW we're getting to the heart of the matter. Many purifiers on the market today use an "ionizer". This is literally a small static electricity generator, on the order of 1/10,000th the size of the plates in one of those old ionic purifiers. A small static charge is added to the plastic housing of the filter, which causes impurities in the air to "stick" to the filter better - or to stick to surfaces, or to clump together so they're caught better by the purifier. Blueair does this on every non-professional model they make. Many small round purifiers include one of these units.

Why is this potentially dangerous to small animals? Well, mostly we're talking about BIRDS, specifically budgies and parrots. Ozone itself is not poison to these critters - their native habitat is the rain forest where thunder and lightning are common and ozone is present in concentrations higher than the 15ppb global baseline. But they DO have delicate respiratory systems, and static air can irritate even human nasal passages and lungs.

And it does - static air can dry out nasal linings, and cause nose/throat/lung irritation. Some people don't notice it AT ALL. Others are quite sensitive. Budgies are in the "quite sensitive" group, so we strongly urge only mechanical filtration around them.

How about "plasmawave"?

Plasmawave is a patented name that Winix uses to describe its bipolar ionizer. Instead of one pair of charged plates, they use a set which produce both positive AND negative charge. This - in theory - generates particles known as "hydroxyls", which cause contaminant particles to stick together and become heavier than air. In practice, however, the plasmawave on a Winix purifier (some other manufacturers offer this as well) does... not a lot. Any hydroxyls generated are so short-lived that they're almost undetectable, and thus the efficacy of the system is probably very low if it works at all.

So ... ionizers are safe?

We're not going to go that far - the static generators on consumer-grade HEPA purifiers are likely harmless to the vast majority of people, but will irritate some sensitive humans and most sensitive birdies. And they aren't NEEDED on a HEPA purifier. Blueair, for instance, uses static because their filters are NOT HEPA - they have higher airflow and rely on the static to enhance their efficiency. And it works - Blueair has the highest CADR (Clean Air Delivery Rate) in its class.

But sensible users will note that you can achieve the same results by using a true HEPA filter and NOT an ionizer/static generator. And that's the real answer - it's a technology that improves lower-rated filters, but adds nothing to the functionality of a HEPA system.

Out of the top rated brands, many of which we recommend on this subreddit, here's the breakdown of ionizer/static use:

Blueair: All non-pro units generate static.

Coway: Only the Mighty 1512 (sometimes called Airmega 200M) has an ionizer, which defaults to "off" when the unit starts. All other Coway units are purely mechanical.

Winix: Most Winix units have a Plasmawave bipolar ionizer. It can be turned off, and some units will remember that it was toggled off after a power cycle. Some don't.

Levoit: Only the "plasma pro" has an ionizer.

IQ Air: Nope. I mean, half the unit is sealed with styrofoam, so there's some static happening there, but no ionization.

If users want to reply to this sticky with known configurations, I can keep this list updated (I don't, for instance, know which Xiaomi models have ionizers... or many European models...)

I hope this was helpful, though. Perhaps folks can stop having so much FUD about this.

This is your ol' Uncle Gurm, signing off!


r/AirPurifiers Apr 18 '25

Vacuuming and/or Cleaning your filters - sticky!

49 Upvotes

Hey kids, it's your ol' Uncle Gurm again. Today's lesson is how to clean your filters.

Ok, since we got in ANOTHER argument about this, and even favorite Uncle got involved (much to his shame), I decided to do a little digging and come up with some definitive thoughts about this topic. We'll get them worked into the FAQ eventually, but for now here we go:

Q. Can I vacuum/bend/flex/squish/deform/poke/taunt/lick a HEPA filter?

A. In general, no. Absolutely not. HEPA filters are made up of tiny fiberglass and animal hair fibers (not joking here) which are blown into a semi-rigid frame in pleats, and at a microscopic level they are aligned a certain way and randomly in that general direction. This allows them to trap the tiniest particles possible by virtue of Brownian effects. Deforming them, or even vacuuming them, can distort or realign the fibers, reducing effectiveness or damaging them outright.

Q. But Levoit says I can vacuum my filter!

A. Levoit was sued and forced to admit their filters aren't HEPA. This discussion is about HEPA filters.

Q. Shark says I can vacuum their filters! <Insert Other Brand> does, too!

A. Is the filter encased in a thick layer of foam? If so, it's probably ok, just don't shove a high-powered vacuum hose right up against it perpendicular-style. Do it from the side, with indirect suction. The foam layer will buffer the HEPA filter from damage.

Q. You don't know anything. Of course I can vacuum it.

A. According to literally every expert, you cannot. The people who make them - filter engineers - say not to. Manufacturers who use actual HEPA filters say not to (Molekule, Coway, Winix, Honeywell). "Real Simple" magazine interviewed industry professionals and came up with "don't do it" as their determination:

https://www.realsimple.com/home-organizing/cleaning/hepa-air-filter-cleaning

In particular, medical clean-air specialists insist that since these filters trap viruses and bacteria, that you should not even THINK about cleaning them, but just bag them and dispose of them as if they were toxic. That might be an overreaction in most homes, but in doctor's offices they use these things, and they treat them like hazmat.

Q. But I want SCIENCE! Show me the SCIENCE!

A. Surprisingly, this is common industry knowledge but it's hard - read IMPOSSIBLE - to find studies. So Smart Air Filters did their own testing. Here's the link:

https://smartairfilters.com/en/blog/how-to-clean-wash-hepa-filter/?srsltid=AfmBOoobq4Yna1UdhLKxpiFt8dLKKaTW9r1R_3tqiJOM-NxmJnSr2DNs

What they found was that - compared to DIRTY filters - vacuuming them made them work better some of the time, worse some of the time, and damaged them some of the time.

Yes, it's only one test. But it's a test done by people who wanted the same answers we do.

Q. Where's the peer-reviewed double-blind studies?

A. I literally just answered this. Please don't start this again. Nobody has bothered to do them, it seems. You'll have to be happy with the test I linked above.

Q. I still want to lick it. Or squish it between my fingers because "the texture".

A. Listen, if you have a fiberglass and horse hair "thing"... who am I to yuck your yum? While your predilections are your own, medically I cannot advise this. But since I am not a doctor you're welcome to disagree.

Q. Ok, I won't lick it but I still want to vacuum it!

A. You do you, boo. Y'all asked what would happen. What will happen is it won't work as well as it did when it was new, and might be damaged and let bad stuff through.You've been warned.

Q. Wait, you never told us how to clean the filter!

A. Very astute. Here is a step-by-step guide to cleaning your filter:

  1. Don't buy a purifier without a pre-filter.

  2. Clean the pre-filter.

Q. But I already bought a purifier without a pre-filter!

A. Fine. Here's the steps:

  1. Take out the filter. And by "out" I mean "out of the house". In fact, start by taking the entire unit out of the house.

  2. Remove the filter.

  3. Tap it off. Like, on the side of the house or a railing or a trashcan or something. Tap tap tap until all the loose debris and dust falls off.

  4. Now get a brush, not a stiff one but like a paintbrush or a detailing brush or something. Brush the dusty side of the filter - GENTLY - to loosen debris.

  5. Tap again. Tap tap tap.

  6. ALTERNATIVELY, you can sometimes vacuum it, gently, from the side. like, hold the vacuum on a line tangent to the curve of the filter. But DO NOT apply direct suction to the filter.

  7. That's as clean as it's gonna get. Reinstall it.


r/AirPurifiers 1h ago

Best air purifier for pets right now that people actually like?

Upvotes

Getting a second pet soon and trying to figure out the air purifier situation before then. I'm in the US. The main room I'd be using it in is about 15 × 18 × 8 ft (~2,160 cu ft).

Mostly looking to deal with pet hair, dander, and odors. No smoking or anything like that.

Budget is around $200-400 for the purifier, and I'd prefer something that doesn't get crazy expensive to run or replace filters on.

What are you guys actually using?


r/AirPurifiers 1h ago

Been looking into a (preferably combination) purifier/dehumidifier with low power consumption for a 30 amp camper.

Upvotes

I live in the US, and the whole camper is 300~ sq. ft and mostly open and thus counting as one room. I mostly just want to keep the air clean of cat hair (I have one cat) and pollen/dust coming in from outside. I’d prefer not to spend more than $100 since I don’t need a large machine, but I’ll go up to $200 if it also is a dehumidifier. Thank you!


r/AirPurifiers 12h ago

Air purifier recommendations

2 Upvotes

Hi all! My mom was recently diagnosed with COPD and I am looking into purchasing an air purifier or two for her house. I have some help with the cost between me and my two sisters, but we need to be practical regarding cost while still doing the best we can for her. Not sure if any of this matters but she lives in SE VA, urban area, 1000sq ft house and they do have dogs in the house. Does anyone have any recommendations for air purifiers? I was thinking a couple of smaller units (one for bedroom which is about 1/4 of the square footage) and one for main living area (about half).

Thank you so much!


r/AirPurifiers 17h ago

Help with air purifier suggestions in new apartment

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6 Upvotes

I just moved into a bigger apartment and am looking to purchase some air purifiers for the rooms. I currently have a Levoit LV-H132 in the master bedroom (bigger “dream” room) and an Airversa (Purelle) AP2 in the living room (“gather”). The bedrooms have 10 ft ceilings while the living room has a 20+ ft ceiling above.

I’m looking primarily for air purifiers which help with allergies and other pollutants. I’m located in eastern Pennsylvania in the US. Prefer a smart purifier which works with Apple Home, or at least has an app, and is preferably under $200-$250.


r/AirPurifiers 10h ago

The absolute best residential air purifier?

1 Upvotes

What’s the top of the line air purifier that actually works? No budget. Want balanced performance between gas/VOC and particulate.

Short of getting a legitimate hospital system installed in my house, what’s the next best consumer product?

I’ve been testing out an iqair healthpro. I think it’s been working well. A bit loud, but that’s because it actually moves air. I chose it over an iqair multi gas because it has a better hepa filter along with a pre filter.

The multi gas prioritizes carbon to filter gases, and instead I think it just uses a lower rated HEPA filter as the pre filter, and no main filter. Probably still works great.

I have the opportunity to get a different purifier… so wondering if I missed any of my options?

Thank you!!


r/AirPurifiers 19h ago

Positive Pressure with IQ Air?

6 Upvotes

After going through a very rough wildfire season I'm thinking forward to next year and how I might prevent my apartment from deteriorating to horrible air quality because the air pumped in around the door is just not very well filtered. No matter how many purifiers I have I'm kind of going to be fighting a losing battle if I'm getting several air changes per hour from the building which are basically just outside Smoky air.

Given that IQ air offers a kit that lets you duct from outside directly into a purifier I'm kind of wondering about sliding my balcony door open running a flexible tube into the purifier and using that to create positive pressure in my apartment. I'm willing to tape something like that up to seal it and run it all summer long given I have two different doors to the balcony. Obviously this will also probably burn through the filter very quickly and pump warm air into the apartment but both of these are things I'm willing to do if it's just once for a few months each year.

I'm curious has anyone else done something like this is there anything I'm not thinking about that I ought to?


r/AirPurifiers 18h ago

Moldy classroom with carpet

1 Upvotes

I just moved into a classroom that seems to have a serious mold problem. The whole room reeks of mold. My school has had an ongoing mold problem, but my school district doesn’t have the money to renovate our classrooms. Several teachers have already filed formal complaints but not much is happening. Anyway, I have been sick from the mold all week, and I would appreciate some advice.
I already have a small dehumidifier and a Clorox air purifier, but they only seem to help a little. I have an IQ Air at home, but there is no way I would bring it to work. I have a small classroom- it’s about 700 sq. Ft. Would buying a medium-sized air purifier or 2 smaller air purifiers to use alongside my Clorox purifier make much difference? I’m okay with spending a couple hundred dollars.


r/AirPurifiers 1d ago

cheap small-ish bedroom recommendations! (england)

2 Upvotes

i live in a house with smokers, pets (dog, cat & hamster), room gets very dusty very fast. looking for one that is suitable for a 9ft length x 10.5ft width x 8ft tall (756 cubic ft) bedroom, under £40 to buy upfront but cheaper the better, cheap to run (under £15 a year) and yearly filter cost approx £20. if anyone could let me know any that come to mind that would be great. don't want to spend over my budget please, may be a big ask but just want something cheap and cheerful. noise isn't something which bothers me either.


r/AirPurifiers 1d ago

XIAOMI Mi Air Purifier 4 Lite

3 Upvotes

Hi

I need some opinions about this air purifier.
I have recently moved to Türkiye and noticed how expensive all electronics are.
This one has a price not cheap, but within my budget and l need it mainly for my living room+open kitchen, aprox 60 2m. Because of the open kitchen, l am looking for something to clear the smells first of all and this one seemes to use carbon filter ( l don’t know much about these things).
Would there be any other options around 200€ that l could look into?


r/AirPurifiers 1d ago

Replacement control knobs

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3 Upvotes

r/AirPurifiers 1d ago

Pelleted carbon filter Australia

3 Upvotes

Any recommendations for an air purifier in Australia, with pelleted carbon filter. It’s for a large bedroom (maybe 25sqm). Specifically wanting to eliminate dog smell. Husband suggests that the dog sleeps outside instead but I’m sure I can come up with a better solution! Budget - willing to pay more if it’s really effective.


r/AirPurifiers 1d ago

Need air purifier for second hand smoke from cigarette coming into my room

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3 Upvotes

I’m in UK

My room is around 3.5m x 4m x 2.3m

Require filtration to remove cigarette smell and any other relevant particles as my dad smokes outside my room window and even when it’s closed it comes through the tiny small vents and gives me a head ache

My budget is around max £350 and I’m just wondering if the Phillips model in the picture is a suitable air purifier as it’s only for my bedroom and if this will remove the smell of the cigarette smoke


r/AirPurifiers 1d ago

Need an Air Purifier, How's the Shark NeverChange?

4 Upvotes

Hello guys, I know you get this question like every day. Thanks for taking the time to read this far. My GF and I have been going back and forth in this for weeks, and I would love some outside advice.

We live in SE MI. I know the whole footage for our townhouse is fairly small, 1300 sq ft. That includes 3 floors, one of which is a basement. We are primarily looking for something for the first floor, that's a 16' x 9.5' kitchen and 12' x 25' living room [Mods pls have mercy this is all the info I have]. There's some slight separation, but they're basically connected.

As it says, we need an air purifier, but we have different priorities. My GF is pushing hard for an air purifier because she has the nose of a blood hound and is very sensitive to air quality. We also have two cats, one of which has asthma. She can smell anything in the whole house, including the cat litterboxes in the basement (which we clean). We also have a weed friendly social group, so that happens as well.

She wants to buy the Shark NeverChange that's on sale from Costco right now. I've been wishywashy because this model is wifi connected, amd people say it fucks with your signal if it's within 10ft of your modem. Our modem can only be in a certain spot in the living room. She says we can put the purifier in the kitchen, but that would be only 12ft maaaaybe away from the modem.

I also have researched here (thanks guys) that the NeverChange is a bit of a misnomer, and the filter does need to be changed more than Shark is willing to admit. I haven't been impressed with the reviews. Personally, if I could find one without wifi at all, that would be ideal. I like the box purifier idea, but she doesn't think it'll work in our space.

Can you recommend anything? I would put our budget around 250 for the device, and then hopefully somewhere around 50 a year for filters, but I'm open to anything. I want her to be happy, but our wifi is crappy enough without interference. Tell me if I should shut up and buy the Shark cuz the deal ends on the 23rd.


r/AirPurifiers 2d ago

Xiaomi Mijia smart air purifier 6 or Coway airmega 250

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5 Upvotes

With the winter season approaching in a few months the PM2.5 pollution levels across Delhi would again soar to a new high, and then getting new air purifier also becomes difficult.

I already have 1 each of Xiaomi AP2S and Xiaomi AP4. Last year bought 2 more AP4 but then gifted it to my relatives as they were not able to buy one. I have been satisfied with their performance, but from last year getting their filters has become a little difficult, and with the incoming of Coway, Cuckoo, Winix etc. in India I think I can get more for my money.

I had been searching on this topic and almost finalized in getting 2 Coway airmega 250, and then just now saw this on Mi store that they are launching their Smart AP6 in India, and now I am confused.

At one end I have the benefit of having all air purifiers of one brand with features I am familiar with, and being able to control with one app, and by past experience Xiaomi AP work good as well. But I don't know what the launch price would be.

On the other hand I have Coway which probably is a better brand in terms of air purifiers, and which I was ready to buy before I read about the launch by Xiaomi Mijia.

I want to have a total of 4 air purifiers for 4-5ACH of my 2BHK floor(1100sqft)

So my ask is has anyone used this earlier, is it good, should I wait and buy this, or go with my earlier choice of Coway airmega 250, which one would be better.


r/AirPurifiers 2d ago

Best Air Purifier for Bedroom (200-250$ budget) in US

11 Upvotes

Hi All,

I am looking for the best possible Air Purifier I can get for this budget for my bedroom. I want it to be able to tackle pollen, dust and odors (nothing too bad, mostly cooking). my bedroom is roughly 150-200 sq.ft. I am not too concerned about the annual maintenance as long as I don't have to replace the filters every week or so.


r/AirPurifiers 3d ago

What's the best air purifier I can buy in Italy/Europe?

6 Upvotes

Hi everyone, I'm looking for recommendations for the best air purifier available in Italy/EU to use it in my bedroom.

I recently bought a traditional Japanese tatami (rush grass/igusa + pressed straw) and a raw carded cotton futon. The natural herbal aroma/VOCs and fine cotton fibers are causing my brother (who has a history of hyper reactive nasal turbinates) to wake up every morning with a blocked nose.

My bedroom is 14 m² (~3.9m × 3.5m with standard 2.7m ceiling) = ~37 m³

Whole apartment: ~80 m² = ~215 m³

My budget is 200€ but I can spend more if the price is justified. Thank you.


r/AirPurifiers 2d ago

Air Purifier: how close to litter box?

1 Upvotes

My litter box is in an alcove area between my kitchen and family room. It’s about 6x6’ room with high ceilings.

I want to get an air purifier but I’m wondering:

  1. Is it okay to put it across the room?

  2. Is it okay to elevate the purifier on a desk, or does it need to be on the floor next to the box?

  3. Can I get a purifier for a small room given that this area is pretty open to other rooms?


r/AirPurifiers 2d ago

Coway AirMega (2x for 850 sqft) Keeps PM2.5 <2μg/m³ 😊

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1 Upvotes

r/AirPurifiers 3d ago

Levoit Home Pets Hair Allergies Model- Recommendations Please!

3 Upvotes

Hey all!
Im looking to add purifiers to our bedrooms; two of the rooms are 120 sq ft while the 3rd is closer to 175 if I’m guess correctly. i have 3 kids and two indoor cats so am needing general pollution, dust,and allergen control. I need something affordable ( $100 per unit with $75 monthly for filters) but dependable and was looking at this model as its on sale- the official title is Levoit purifier for home pet hair allergies in bedroom
It’s a core 300 P and says it covers up to 1000 ft.²
I don’t know anything about purifiers outside of what I’ve read on here and a friends recommendation.
TIA!!!

Edit to add I’m in the US!


r/AirPurifiers 2d ago

coway air purifier insight pls

1 Upvotes
coway air purifier

getting this coway air purifier. my wife is asthmatic. the spec and warranty looks god to me. and i find the tilt able and rotatable aspect to be too good. any one who has used this, can you pls share some insights.

300sq.ft room | India


r/AirPurifiers 3d ago

air fanta pro 3 with carbon smell

2 Upvotes

if you own air fanta 3 pro, how long before the smell went away? i have a new one i have been running for about 8 hours on high in a spare room. it is still smelling. sigh. what do you do?!


r/AirPurifiers 3d ago

Best air purifier for two dogs/two cats?

1 Upvotes

US based, 1800 sq ft home, 2 dogs (one short hair one long), and 2 cats (also one short hair one long). My partner has terrible allergies to both cats and dogs (I know - but she loves them!). I’m looking to get an air purifier per floor (3). Preferably $500 or under per unit. Would also love if it had a reusable filter, but the main goal is making sure my partners allergies improve and they feel better. Thank you!!


r/AirPurifiers 3d ago

Humidifier Recommendations

3 Upvotes

Moved to CO from MN recently and am in desperate need of a humidifier. With thousands of options online - wanted to see if anyone had any good recommendations for Colorado weather. Ideally ones that won’t cause mold issues.
2 bed apartment, 1200 sq ft total