Air purifiers, are they any good and how do I know which one to buy? Anyone know the "real" deal on these things?
November 9, 2007 12:46 PM   Subscribe

Air purifiers, are they any good and how do I know which one to buy? Anyone know the "real" deal on these things?

I recently adopted two cats and I have minor allergies to cats. Also, am pretty allergic to dust and mold. I also have mild asthma. My boyfriend has the dust and mold allergies and moderate asthma.

We are looking to buy an air purifier to help reduce allergens, however it is overwhelming to try and understand what type of air purifier to get. I don't understand this carbon thing and some are class II certified and some are $800 and some are $150 amd some have replacement HEPA filters at $80 and some for $200. Does anyone actually know the real difference and what key things to look for? I am about to just vacuum more often and be done with it. We have hot water heat in radiators so at least we don't have forced hot air, but we are in on the second floor of an old house that seems to get a lot of dust. Also, with the cats has come the litter, which I think maybe myself AND the cat are allergic to, its clay litter.

I am feeling itchy thinking about it all.
posted by Carialle to Health & Fitness (13 answers total) 9 users marked this as a favorite
I have three Honeywell air filters and they do help with the cat hair and with dust in general. Recently Honeywell did some studies that showed if the carbonized pre-filter is changed regularly there was no need ever to change the HEPA filter, which is great in terms of cost saving.
posted by ikkyu2 at 12:48 PM on November 9, 2007

My girlfriend and I both got this Honeywell filter and they've been very helpful for dust and mold issues in our apartments. We have to clean the prefilter every month or so but I don't think we'll ever have to replace anything.
posted by Hermes32 at 12:57 PM on November 9, 2007

VENTA Airwasher

Very good, no need for a filter but a bit pricy.
posted by yoyo_nyc at 1:03 PM on November 9, 2007 [1 favorite]

There's nothing wrong with the cheapter hepa filters. Absolutely do not go near any 'air ionizers.' Those are scams.

If you have bad allergies then you should also replace your vaccum with a hepa filter vacuum. Youre just going to be recirculating the allergens with a normal one.

Its also a good idea to get two. One that you can leave on in a main room like the living room and another smaller one just for the bedroom.
posted by damn dirty ape at 1:08 PM on November 9, 2007

My experience, with a room sized hepa unit, is that the difference is very noticeable, when I stick my face right in the air flow, but not very noticeable otherwise. It is a lifesaver when my allergies are bad, but also very noisy..

So, don't go small, because you need to circulate a lot of air to be effective.
posted by Chuckles at 1:58 PM on November 9, 2007

I have the same type of allergies. I have a Vorndao AQS25, as does my brother who has HORRIBLE hay fever and these filters are amazing. The most remarkable part is when I run my filter in my bedroom overnight, I don't wake up with morning mouth. The scary part is when you clean the prefilter and you see the visible junk the filter is pulling out of your air then imaging what it pulls out that you can't see!

I use the filter to "scrub" a room and I can feel a difference in the air quality almost immediately.

As far as the carbon and HEPA combo, you can read about it here.

Also, if you are allergic to your cats, try giving them a bath, most people are really allergic to cat saliva on the animal's fur. I lived with a girlfriend who had a cat, with the filter and regular cat baths I was great - no allergy problems at all.

I am no way associated with the Vornado, beyond being a VERY satisfied customer.

Hope this helps
posted by Fuzzy Dog at 2:40 PM on November 9, 2007 [3 favorites]

I don't have any air purifier experience...but we use a vacuum with a HEPA filter, and that seems to really help. We have people come over all the time that are allergic to cats and dogs, and they can't tell we have them if we vacuum right before hand. So in addition to whatever air purifier you get, I , too, would suggest a HEPA vacuum.

Also, only someone with the name "Fuzzy Dog" would suggest bathing a cat regularly... :-)
posted by JibberJabber at 3:20 PM on November 9, 2007

We use an older version of one of these: Friedrich C-90B. It's actually electrostatically based, but it has a huge ass fan in it to, you know, move air past the charged plates. Consumer Reports rated it very highly some years ago.

Outside of a large particle/carbon filter, the device is filterless. To clean it out, you basically take out the plate module and wash it in the dish washer.
posted by chengjih at 4:07 PM on November 9, 2007

I have a vacuum with a HEPA filter, and using that daily has made a tremendous difference for me. You might find you have less allergic reactions using the vacuum than having to invest in an air purifier. Mine is a Eureka Mighty Mite and it was under $100. I had one for 13 years before replacing it with the HEPA version. They are indestructable.
posted by 45moore45 at 8:17 PM on November 9, 2007

I've had fairly good luck with the Vornado, too.
posted by Coventry at 8:33 PM on November 9, 2007

I have a couple of Honeywell HEPA filter units, and although I change the carbon pre-filters 5 or 6 times a year, I'm lucky to get a full year out of the inner paper HEPA filters. I live in Florida, where there's year round plant pollen, and have a dog.

But the main cost in using portable air filters is not the replacement filter media, it's the energy cost of moving air through HEPA filter resistance. As Chuckles notes, you need to move a lot of air through an air filter, for it to be effective (as in, move all the air in a room through the filter, several times every hour). A single room unit, running at high setting 8 hours a day, is going to use a couple dollars worth of electricity, at average North American electricity rates (where I live, electricity costs just about the U.S. median rate). If you run the devices longer, your power usage goes up proportionately. So, per month, per room sized unit, you can spend $50 - $60 in power cost, running it for a couple hours at a time (enough to recirculate the room air 4 or 5 times each run), several times a day. You'll definitely have reduced airborne dust, but unless you get a HEPA equipped vacuum cleaner, and clean/replace its filters regularly, too, you may not see much difference in the amount of visible dust on your furniture, since vacuuming kicks out a lot of large particle dust from the average home vacuum cleaner, which stays low, and falls out of the air fairly rapidly, due to gravity. You can look for allergy control vacuum cleaner bags, if your current vacuum cleaner uses disposable bags, and in my experience, they do a much better job of trapping dust than standard bags, and are worth the additional cost. You'll have to change them much more frequently than standard bags, because they catch more dirt and fill up faster, but that is kind of the point, isn't it?

Since you have radiator heat, you don't have ducting, and so centrally installed electrostatic air cleaners aren't an option for you. Portable electrostatic units don't really move enough air, or create enough an electrostatic field to do what they claim to do, and as damn dirty ape suggests, I agree you shouldn't waste money on such devices.

Finally, as the father of a son who grew up with asthma, and still, as a 35 year old man suffers with breathing problems, I'd really question whether keeping multiple cats in an apartment, even one with lots of air filtration and great cleaning efforts, is wise. Many allergies get worse with continued exposure, and no matter how much you clean, or wash the cats, they'll be a continuing source of dander. If I were you, before I loaded up on air filtration and improved vacuum technology, I'd probably speak to a qualified allergist, and make sure my asthma was always well controlled, even if it meant finding other homes for the cats, and taking up tropical fish.
posted by paulsc at 8:39 PM on November 9, 2007 [2 favorites]

Allergy and asthma sufferer here. We bought a Whirlpool Whispure in the spring, and have always used a 3M Filtrete filter in our air and heating system and a HEPA filter in our vacuum cleaner. The Whispure is very quiet. Got it for $230 at and were very happy with their service.

I've noticed that my allergies have not been as bad this summer and so far this fall. And we have two cats and live in California's Central Valley, so our air quality isn't exactly ideal.
posted by DakotaPaul at 10:22 PM on November 9, 2007

We have a Honeywell in the living room thats been on constantly for years. Double-digit critters make it imperative to have an air cleaner.

But why I'm posting this is because we've got an ionizer type in the bedroom. I've read several studies which show strong findings that it shouldn't work well, but I swear when we turn it off we feel the difference within a day. It's pretty much limited to taking out very fine particles, but it's quiet and low cost to run.

I've got an enviromental science background, and I'm trained to believe studies. Possible explanations are that the particulate load in the bedroom is small enough that an inferior product works well enough, or that the ionization causes a chemical change in some substance. I note that ozone can be generated by these and is considered a pollutant. It does help with the aesthetics of, um, outgassing by the dog.

At any rate, I'd still start with a Honeywell or similar product for a first filter. As to the other, well, something is happening and I don't know what it is...
posted by dragonsi55 at 1:27 PM on November 10, 2007

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