BUYING A HOME AIR CLEANER...A PRIMER
I have gone through a lot of air cleaners, and one of the problems I had was finding a good source of information from someone that had actually TRIED them. I didn't need product reviews of any particular air-cleaner, but rather a guide on what to keep in mind while shopping. Most web pages that I came across were also interested in selling me something, so I never knew what to trust.
I have allergies. Not the worst ones known to man, but bad enough to where I was willing to open my wallet in search of relief. The allergist had recommended an air cleaner as a way to help cut down on some of the problems I was having (especially considering I have a slight allergy to cats and own three of them!)
I will try to be brief and just highlight the important things I have learned, though it goes against my nature.
- Size. This is one of the most important factors to consider, and as a rule of thumb, bigger is usually better. Air cleaners work by sucking in all of the air in a room, running it through a special filter, and then pushing it back out. The larger the filter is and the more air it can pull through it the faster all the air in your room is cleaned. In order to be effective at helping with your allergies, an air cleaner must be able to change the air in the room at least 4 times an hour. A much better number would be 6-8. They call this the ACH rating, or "air changes per hour." If your air cleaner is too small it will not be able to exchange the air in the room fast enough and some allergens will be left. (Cleaners will advertise a CADR more...this is "clean air delivery rate." It is more accurate because it tells you how much clean air the machine will put into your room per minute, which is a great stat for comparing air cleaners if your room doesn't happen to be about the same size as the one they use to measure ACH, which is 20' X 20') MAKE SURE THAT THE AIR CLEANER YOU BUY FITS YOUR SPACE, ESPECIALLY IF THAT SPACE IS LARGE.
- Containment. It doesn't do much good to keep an air cleaner running with the windows open. Remember, the air cleaner only works when it is able to keep recirculating the same air in a room. Think of it like sweeping...it might take several passes of the broom to get all the dirt off the floor. If the air cleaner is in a room with the door open, or if it is in a wide open living room that connects to all the other areas of your house, it will not do as good of a job at cleaning the air. Try to contain the areas of your house as much as possible. Keep the bedrooms that have the air cleaners in them closed. If you are faced with a layout that is large and can't be easily closed off, put the air cleaner in the location you are most likely to be as the air in that general vicinity will stay cleaner.
- Quantity. Unfortunately, if you really want cleaner air, you are probably going to have to consider buying more than one air cleaner. One unit, quite simply, can't keep the air in a whole house clean. Start with the bedroom (you spend a lot of time in it while asleep, remember.) It is probably a smaller room and so it is easier to clean than a living room. If your finances allow it, branch out from there with more.
- Run it all the time. This goes against the eco-grain, but what can you do? Remember, an air cleaner works by constantly sweeping the air. If you only turn it on when you go to bed or when you are home it will take a while before it can "catch up" and clean the air in the room. Running your air cleaner all the time is the best way to give it the time it needs to do its job.
- Noise. The bigger the air cleaner, the more noise it makes; that is an unfortunate byproduct of having a device that uses a fan. Still, some models are quieter than others. If you can find statistics for the decibels of noise a particular air cleaner makes you can use that to compare with other air cleaners sight unseen (remember, the higher the DB rating is the louder it is.) Otherwise, turn them on at the store to their highest setting. It might not seem like a big deal (it's just white noise, really) but it can get in the way if you are putting it by your telephone or by the TV.
- HEPA media. The HEPA filter is the heart of most air cleaners. It is what traps the junk in the air. HEPA is HEPA...if you see that rating on an air cleaner it is guaranteed to remove at least 99.97% of allergens down to 3 microns. This covers dust mites, pet allergens, mold, and pollen...most common allergens. Still, this HEPA filter costs money. Compare the price of replacement filters. Keep in mind, some units (especially the larger ones) use several small filters versus one big one. Factor that in as these costs can add up! Like a computer printer, it is not the price of the device that kills you...it's the ink.
- HEPA-type filter. Be careful with the word "type." That means it is not a real HEPA filter and won't catch such small particles. You might not need this though if you are not allergic to anything smaller than the filter can snag.
- Cleanable HEPA, or just plain cleanable. Some air cleaners will have a HEPA filter that you don't need to replace, which can save you some money (be careful, though, if it doesn't say HEPA. Make sure the non-HEPA filter will be able to get rid of the allergens you are trying to get rid of if you want to get one of these.) You pull it out, knock it on something outside (like beating a rug, but more gentle,) vacuum it, and then just put it back. I have one of this type right now. It works well (though I don't like cleaning it as dust flies everywhere...get someone else to do that if you can.) My only complaint with this type is that as the filter begins to collect dirt I think that they get a little noisier...not louder, but a little rattle-ey. That's usually when I know it is time to clean it. Also, many of these models do not have a carbon filter with them, which brings us to...
- Carbon Filters. The "activated carbon filter" is the black looking sheet that usually sits in front of the HEPA filter. This is the piece that removes bad smells from the air as well as some chemicals. This is a critical piece if you are also buying an air cleaner to absorb these little bits of nastiness and not just to get rid of cat dander. FACTOR THIS IN! These filters seem to need replacing faster than the HEPA ones. They aren't as expensive, but they aren't free, either. If you are trying to rid your house of the smell of smoke or animals, you can run the air cleaner 24 hours a day and not get any results if the carbon filter is used up. From my experience, even a good home air cleaner will do only a marginal job of getting rid of odor, and that is only if the carbon filter is fresh. Here is a tip, though, to save some money: Instead of buying the carbon filter made just for you unit, you might be able to save money if you buy a much larger one and then cut out two smaller ones from it. I have done this without any problem...it's like cutting a Brillo pad.)
- Ion generators. Don't get one of these. They make the air smell nice (kind of like after a summer rain) but are generally not thought to be safe. They change the electrical charge on the particles that go into the machine, making them "stick" to things when they come back out. The theory would be that they will stick to your furniture and floor (in the way that magnets stick to things) and that you can just vacuum them up or dust them away. Still, these machines produce OZONE, which is not very good for you. Also, some people feel that the same "ionizing" that makes the particles stick to furniture also make them stick to your lungs. In general, I would research this topic out carefully before getting one. Don't confuse them with our next topic, though...
- Hybrid filters. These are machines that use both a HEPA filter and and Ion generator. The idea is that the recharged junk in the air will stick to the HEPA filter and not be blown back out into the room. This works pretty well as long as the HEPA is kept in good shape. You are still making some trace amounts of ozone, though, which you can notice by that "just rained in the morning" kind of smell. I have several of these types of air cleaners and I have found that as long as I keep the ion setting to "low" things are okay. When I turn it to "high" in a closed bedroom the smell of ozone is overpowering (and that can't be good for you!) Remember, though, that some people would argue that some of these charged particles can slip past the filters and begin to stick in your lungs. I have not been able to look in mine to see : ) I just keep it on LOW and that seems to be fine.
- UV lights. Some air cleaners have a little UV light that shines inside of them. This is supposed to kill off bacteria and viruses that come into the machine with the air. I don't know if this works or not. It is a feature on one of my machines, and I can see it glowing blue in there, but how effective it is I just don't know. It is something else that you have to replace in time (just like a light-bulb) and it is not a part you just go down to Target to buy. The only time I think it is cool is if someone in the house is sick and you put it in a closed room with them. I feel a little better about going in there with the chicken soup (even though it is probably all in my mind as germs are everywhere else in the house!) UV filters are used a lot in hospitals, so they must work, but you will have to decide for yourself if it is worth the extra expense.
- The Ionic Breeze by Sharper Image. Ah, here is an interesting (and controversial) one. They call these "electrostatic precipitators." They work in a similar way to the Hybrid Ion Cleaners, but instead of using a HEPA filter they use a metal plate. As the particles become "sticky" they attach themselves to the metal plate (again, just like opposite magnets stick to each other.) When the plate gets dirty you take it out, wash it off, and put it back it. No filters to replace at all. And because they don't use a fan to push the air through they are totally silent (except when they are dirty, and then they crackle a bit.) So how do they move the air? I don't know...something to do with the air outside the unit being attracted to the metal plates (because of that magnetic-type phenomenon) which draws it in and creates a "breeze." It is very gentle and you only feel it if you put your hand next to the grill. As you can guess, this leads to a very low ACH and is a reason why many people blast these types of cleaners (The Sharper Image Ionic Breeze, for example) as being lousy. How can something that moves so little air possibly do a good job of getting it clean? Also, as with the ionizer, a small amount of ozone is produced (though, frankly, it is so small on the newer units that I don't consider it a drawback.) Well, I have one of these, too. When you run it overnight in a room the next morning it smells fresh and clean. And because it is quiet, it does not get in the way of watching TV. But does it work? I can only tell you the two things I know for sure: A) it is the only air cleaner that I can put next to the kittie litter boxes that both keeps the house smelling cat-free and also doesn't scare the little guys, and B) When I clean it, the plates are covered in a dusty fuzz, so I know it is taking SOMETHING out of the air. Consumer Reports hates these cleaners, but I like them. It's a tough little sucker if it can clean the air by the cat boxes by itself. It saves me from endless carbon replacements! Of course, prepare to dig deep into your wallet to get one. Now that Sharper Image is out of business I am not sure if the price for the Ionic Breeze on the secondary market will go up or down, but there are other manufacturers out there ready to fill the gap left by SI's demise..
So in summary, here is what I have to say:
- Make sure it is big enough to do the job
- Make sure you have more than one of you need them
- Make sure you budget to replace both carbon and HEPA filters
- Make sure if you buy a non-HEPA cleanable filter that it can trap the particles you are allergic to
- Make sure you replace the carbon filter frequently if you want it to trap gasses and odors
- Make sure you understand the fan in an air cleaner is non-offensive, like white noise, but can be LOUD like a fan
- Make sure you understand that you must run the air-cleaner all the time for it to work well
- Make sure you keep the rooms you want to clean closed off as much as possible
- Make sure that you are not buying an ion generator
- Make sure you don't hold the bad qualities of an ion generator against the ion/HEPA hybrid
- Make sure you are not confusing the ion/HEPA hybrid with the "electrostatic precipitator" AKA Ionic Breeze
- Make sure to vote for this guide if you think it was helpful! : )