# Air Purifiers are a Ripoff - Whirlpool ap51030k

Mentor
My girlfriend has three cats and an aversion to seasons, so I bought us a room-air purifier. It's a Whirlpool ap51030k, which I bought on Amazon for $300. I did a bunch of research and it got good reviews as a decent mid-level purifier. Being that I work in HVAC I have some knowledge of air filtration, so going into this I pretty much knew what these things do: They are just a box with a centrifugal fan that pulls air through a quality filter. I also know what they should cost (not much) and what it takes to design/make one work well (also not much). Now the first thing that you find when you start researching these things is that they cost several times more than you would expect. But, constrained by market realities, you look for a decent one at a price you are willing to pay. The next thing you learn is that 90% of air purifier review websites exist for the purpose of selling you their no-name brand air purifier and the reviews are fake. Because of this, I decided at the outset that I was going to buy a brand-name I knew I could trust. Names like Holmes, Honeywell, Whilrpool. Major manufacturers should produce respectable products and are less likely to fake their own reviews. So I found some review articles that looked trustworthy and also sampled the personal reviews on generic retailer sites (ie. on Amazon, not on airpurifiers.com), which were shockingly helpful (see the HDTV sound quality thread for the opposite). Here's what I found: 1. It is easy to recognize total scams if you aren't a complete idiot. For example: Since an air purifier is a filter with air flowing through it, good filtration requires a fan. Duh. My favorite, though: Plants are not air purifiers and even if they were, you don't have to buy a device to house a plant you already have. 2. Filtration quality varies widely, but since it isn't hard to make a quality air purifier, it isn't hard to find ones with good filtration. The basic principle is: bigger is better. Bigger fan and more filter surface area means more air gets filtered. 3. These things are loud. There's no getting around this and it is to be expected: High quality filters have high pressure drops and as a result, require high pressure centrifugal fans, spinning at high rpm to pull air through them. Now when I say "there is no getting around this," what I really mean is that you'll never get a centrifugal blower to sound like a ceiling fan on medium speed, but there are things you can do to make them sound less like a helicopter trying to land in your driveway. So you take sound into account when selecting. 4. Because it isn't enough to screw you over the purchase price, air purifier manufacturers screw you over filter replacement as well. My first choice purifier was a Honeywell 50250-N with a cleanable filter, but a review website (and many individual reviewers) warned me that not even Honeywell's website was clear about exactly which model they were selling. Seems one model has a cleanable filter and another one doesn't and they differ only by the letter at the end of the model #. So after an hour of looking for it, I gave up. But I'm not going to get arrested for cleaning a non-cleanable filter, so this doesn't bother me much. And that's pretty much it. Like I said, not rocket surgery. So I bought the Honeywell: It is "reasonably" priced and got good marks for sound and filtration. My first reaction when opening the box was: "What a piece of garbage. Did I really just pay$300 for this?"

It is made entirely of plastic. There's more metal in the 15 space heater sitting next to it. And it's thin, flimsy plastic too. I could probably drop-kick my space heater down the stairs and it would survive, but I pray my girlfriend's cats don't knock this thing over. So I plug it in and turn it on. Yeah, it's loud. But it does have a neat little "sleep" button that puts it down to low speed for 8 hours whiile you sleep, then returns it to its previous speed. It also has filter life monitoring. Fairly basic controls overall, though. On closer examination, I look down into it and see that the fan appears to be wobbling. So I turn it off. Not only is it wobbling, but it is also out of balance: it slows to a stop, then rotates backwards and settles into a heavy-size down configuration. Unreal! (speaks well for the low resistance of the bearings, though I guess). After a few days of use, it's already making a ticking noise, indicating that perhaps a bearing is already failing. So I'm going to try to send it back and if I can't, balance/align it myself. I also see that it is equipped with sound attenuation. Nice. 'Course it is just a styrofoam baffle at the outlet and a styrofoam wrap around the back side of the square fan casing. With just a little bit of effort and money, they could have made a more aerodynamic case and lined it with some actual sound attenuating material and probably made a huge difference. So I don't want to oversell it, but again, this thing is crap. One would think that with a 97% profit margin, it would pay for a company with a reputation to put just a little bit of effort into quality, but nope: gotta squeeze that to 98%, particularly since I'm sure everyone else does it. If one were to consider a comparison between this and other room-level HVAC devices, it would compare pretty unfavorably to a room humidifier and be more expensive than a space heater if only because it's bigger. It really isn't worth more than50 -- assuming that my out of balance/alignment fan isn't the norm. If I ever get bored and grumpy, I'll build my own and prove that it can be done cheaper and better.

My girlfriend says it seems to be helping her alergies and is happy with it. So in conclusion, I would recommend purchasing the Whirlpool ap51030k to make your significant other happy and redirect your vomited frustrations over what a piece of crap it is onto random people on the internet.

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noodleman and billy_joule

Ryan_m_b
Staff Emeritus

So in conclusion, I would recommend purchasing the Whirlpool ap51030k to make your significant other happy and redirect your vomited frustrations over what a piece of crap it is onto random people on the internet.

turbo
Gold Member

My wife and I have a Honeywell HEPA air purifier in the bedroom. The only time it ever needs attention is when the carbon-foam pre-filter gets loaded with dust and dog hair. Not a problem. Plus, you can pick one up for around $150 or so. The machine has sensors to let you know when the pressure-drop across the pre-filter or HEPA filter indicates that the filter(s) are getting dirty. OmCheeto Gold Member ...If I ever get bored and grumpy, I'll build my own and prove that it can be done cheaper and better. My girlfriend says it seems to be helping her alergies and is happy with it. So in conclusion, I would recommend purchasing the Whirlpool ap51030k to make your significant other happy and redirect your vomited frustrations over what a piece of crap it is onto random people on the internet. I had a similar, but somewhat opposite experience back when I bought my house in '89. Though the conclusion was identical. I noticed that I slept better in the summer than the winter, as I kept my window open all night. Fresh Aire! Unfortunately, I was not willing to leave my window open all night when it's 35'F outside. My solution was to build a window mounted counter-flow heat exchanger out of hobby wood, aluminum foil, a pair of 12 watt/32 cfm muffin fans, and the obligatory roll of duct tape to hold the whole damn thing together. It worked perfectly, at a grand old price of around$30. I had to build one myself as I didn't even know what to call such a monster back then. I did run across such a device in a store one day about 5 years later for 10 times the price. And today I've found that they have an official name: http://www.google.com/products/cata...X&ei=u6m-TpjnFeSMiAKEvNmLAw&ved=0CIoBEPMCMAE", with a not so cool price of \$449.

hmmm.... Perhaps they use more aluminum foil than I did.

*When discussing my invention with my friends, I referred to it as a "Fart Gas Extractor", as "Counter-flow Heat Exchanger" just made me sound snooty.

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Pythagorean
Gold Member

We have fire smoke summers from the forest fires and smoggy winters from the inversion layer.

I bought a hepa filter fan. Bearings in the fan went out after a year of use.

Moonbear
Staff Emeritus
Gold Member

My girlfriend says it seems to be helping her alergies and is happy with it. So in conclusion, I would recommend purchasing the Whirlpool ap51030k to make your significant other happy and redirect your vomited frustrations over what a piece of crap it is onto random people on the internet.

My boyfriend keeps muttering something about, "men can be right or they can be happy." It seems to fit the scenario here...though, in our case, he's the one with the air purifier and I'm the one that tells him it's an overpriced fan and to leave it off because I don't want the draft from a fan in winter and it's too noisy. It would be interesting to remove the filter and just leave the case surrounding the fan and see if people still thought it helped with their allergies.

My question to you is: do these things actually exchange enough air through them in an hour to reasonably think they could adequately filter enough room air to have more than a negligible effect on air quality?

Mentor

Yes, actually the "good" ones do a respectable job. Unfortunately though they pretty much have to be loud to work well. Good filters are tight so they require a lot of pressure to push the air through and to do that they need to spin fast, which makes them loud.

Chronos
Gold Member

My computer case is mostly perforated metal and it does a fabulous job removing dust from the air. I have to clean it almost daily.

Consider the fact that there are silent systems that are very highly effective. One such used to be made by (or for?) Sharper Image, but the one I eventually bought (the Ionic Pro) worked fine until it needed its first cleaning. Hasn't been anything except a very expensive tripping hazard since.

Therefore, it is not altogether true that air filtration systems have to be loud to be effective. And no, I am not a shill for the companies that make the ionic air purifiers, just someone who has experienced the sharp rise in air quality that such filtration systems can provide.

JonDE

Yes, actually the "good" ones do a respectable job. Unfortunately though they pretty much have to be loud to work well. Good filters are tight so they require a lot of pressure to push the air through and to do that they need to spin fast, which makes them loud.

I'm not very knowledgeable about how hepa filters work, but it seems to me that you could just find one slightly smaller then your exhaust vents in your house, find a way to insulate them to prevent blow by. Then all you would have to do is check your air flow and the amperage on your blower motor to make sure you are not overtaxing it, and run your fan for your air conditioner continuously.
Your air should be already filtered through the normal filter for you air conditioner, so the hepa filter wouldn't need to be changed or cleaned too often.
For some reason this sounds too easy and cheap to work, so what am I missing?

Pythagorean
Gold Member
Making a good seal that lasts and looks marketable is an art, methinks.

Moonbear
Staff Emeritus
Gold Member

I'm not very knowledgeable about how hepa filters work, but it seems to me that you could just find one slightly smaller then your exhaust vents in your house, find a way to insulate them to prevent blow by. Then all you would have to do is check your air flow and the amperage on your blower motor to make sure you are not overtaxing it, and run your fan for your air conditioner continuously.
Your air should be already filtered through the normal filter for you air conditioner, so the hepa filter wouldn't need to be changed or cleaned too often.
For some reason this sounds too easy and cheap to work, so what am I missing?

Not everyone has central air conditioning, and you wouldn't have it on at all in cooler weather if you have baseboard or radiators for heating rather than forced air.

OmCheeto
Gold Member

I'm not very knowledgeable about how hepa filters work, but it seems to me that you could just find one slightly smaller then your exhaust vents in your house, find a way to insulate them to prevent blow by. Then all you would have to do is check your air flow and the amperage on your blower motor to make sure you are not overtaxing it, and run your fan for your air conditioner continuously.
Your air should be already filtered through the normal filter for you air conditioner, so the hepa filter wouldn't need to be changed or cleaned too often.
For some reason this sounds too easy and cheap to work, so what am I missing?

You're not missing anything! As long as you have central heating and cooling, as Moonbear pointed out.

I installed a very similar modification to my mothers system back in 1985, as my brother had dreadful allergies. Her system had a very nice feature in that you could turn on the fan without turning on the heat. Made it great for the summertime. Unfortunately, my brother is not much of an accountant, and insisted that the 124 watt fan consumed too much energy. So he probably ended up spending twice on kleenex than he would have spent on electricity. Not to mention he was miserable 6 months out of the year.

The only difference between your system and mine was that I installed both filters on the intake of the furnace. The rough filter to catch bugs and stuff first, and the HEPA filter to catch the allergens.

Mentor
Consider the fact that there are silent systems that are very highly effective. One such used to be made by (or for?) Sharper Image, but the one I eventually bought (the Ionic Pro) worked fine until it needed its first cleaning. Hasn't been anything except a very expensive tripping hazard since.

Therefore, it is not altogether true that air filtration systems have to be loud to be effective. And no, I am not a shill for the companies that make the ionic air purifiers, just someone who has experienced the sharp rise in air quality that such filtration systems can provide.
I'm glad you like it, but testing shows that fanless air purifiers don't work very well and in particular the Sharper Image one was such a dud that it was largely responsible for them going bankrupt. The biggest part of the bankruptcy though wasn't the filtration performance, but the production of ozone, which is poisonous.
http://www.air-purifier-ratings.org/Sharper_Image_Ionic_Breeze_Review.html
http://en.wikipedia.org/wiki/The_Sharper_Image#Consumer_Reports_lawsuit

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Mentor

I'm not very knowledgeable about how hepa filters work, but it seems to me that you could just find one slightly smaller then your exhaust vents in your house, find a way to insulate them to prevent blow by. Then all you would have to do is check your air flow and the amperage on your blower motor to make sure you are not overtaxing it, and run your fan for your air conditioner continuously.
Your air should be already filtered through the normal filter for you air conditioner, so the hepa filter wouldn't need to be changed or cleaned too often.
For some reason this sounds too easy and cheap to work, so what am I missing?
Definitely the first step for anyone should be to start with a higher quality filter at your air conditioner and return filter grilles are great too, but the risk is that the extra pressure drop can affect the performance of your air conditioner. Often, AC fans are oversized, so it isn't typically a big risk though.

Pythagorean
Gold Member
russ, I don't suppose you could suggest specific good models/brand names for a small apartment (occupied room is a bit larger than 2000 cubed feet, 20x10x10).

In the winter, we all have all kinds of air quality advisories because of the inversion layer. Sore throats this time of year are commonplace. Our last hepa filter fan crapped out within a year of use (bearings in the fan). It was an Idylis.

I'm glad you like it, but testing shows that fanless air purifiers don't work very well and in particular the Sharper Image one was such a dud that it was largely responsible for them going bankrupt. The biggest part of the bankruptcy though wasn't the filtration performance, but the production of ozone, which is poisonous.
The fact it failed completely after the first cleaning (and I followed very specific steps to correctly clean the unit top-to-bottom, some of which were not mentioned in the manual's "How to Clean Unit" section) turned me sour on the whole idea of air purifiers, to be honest. However, I did notice a big improvement in air quality while it did run!

Noise level does not indicate effectiveness (as witness the Dyson fan-units I've seen (and experienced at Best Buy) which are close to silent, yet blow a surprising amount of air) and too many HEPA filters are seriously overpriced for what you get, and often not washable. This is bad business also. I understand that HEPA filtration does indeed work, but the associated costs are ruinous if one is on disability, as I now am. Finding an effective, inexpensive method to filter the air in my house is a need, however, as too many of those in my house are allergic to some of the oddest things. Will keep researching!

Now, a purifier based on Dyson technology plus a high-quality washable allergen filter should work pretty well, don't you think? Only time and testing can prove one way or the other, however.

Mentor
russ, I don't suppose you could suggest specific good models/brand names for a small apartment (occupied room is a bit larger than 2000 cubed feet, 20x10x10).
Sorry I didn't see this before...

....I haven't done any testing any besides the one I bought, but there are some good reviews out there. You just have to be a little careful that the review you are reading is actually a review!

Mentor
Now, a purifier based on Dyson technology plus a high-quality washable allergen filter should work pretty well, don't you think? Only time and testing can prove one way or the other, however.
Dunno - what is "Dyson technology?"