Air-O-Swiss AOS Ultrasonic Humidifier - 7135
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Our Price: $179.99 Availability: Usually ships in 24 hours Buy Used: from $99.99 (click here) Category: Kitchen See more product details |
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Kitchen and Housewares Reviews of Air-O-Swiss AOS Ultrasonic Humidifier - 7135
Customer Review: Air-O-Swiss 7135, Good but not good enough...
Summary: 3 Stars
I bought the Air-O-Swiss believing that for the kind of money I was spending I would be getting the ultimate in humidification technology. Well it turns out that's true, however there's one caveat. As others have mentioned here the hygrometer is not very accurate and it reads terribly low. When I compare the hygrometer reading of the 7135 against my other thermo hygrometers it (7135) reads about 15~20% too low. This wouldn't have been a problem had Air-O-Swiss provided the ability for users to set the humidity setpoint from 0~100%. Instead they've provided an absolute lower limit of 40% RH which means in reality you'll end up driving the room well over 50% when the unit is set for 40%.
I contacted Air-O-Swiss about this and the gentleman on the phone told me that it's probably the #1 complaint they get about this model and the others which are similar to it. I believe I have figured out the source of the problem and have shared that information with Air-O-Swiss. If you feel like a boring engineering diatribe read on, otherwise I've said everything that's useful for John & Jane Q Consumer.
In my opinion the problem with the unit is as follows. Relative humidity, the parameter controlled by this unit, is as its name implies, relative. The value indicated on the face of the unit is supposed to indicate how close to saturation (i.e. 100% RH) the air is at a given temperature. If the temperature of the air mass goes up while you keep the total amount of water vapor in the air constant the RH% will fall as the temperature climbs. Likewise if you keep the total amount of water vapor in the air constant while lowering the temperature of the air mass the RH% will go up. Stated simply, warm air can hold a lot more water than hot air.
This unit calculates the RH using two electronic sensors which are inside the main housing. One is a thermistor (negative temperature coefficient resistor) whose resistance varies as a function of temperature and which is read by the microprocessor inside of the unit. The other is a hygrometer, probably a capacitive type whose capacitance varies as a function of humidity. Readings are taken from the hygrometer and using the temperature reading from the thermistor a figure is calculated for relative humidity. This works really well so long as the sensors are accurate. We'll assume the hygrometer is perfectly accurate. However the temperature sensor (thermistor) is not. Unfortunately it has been placed inside of the box next to various electronics and not too far from the heater which warms the water. The result is that the unit corrupts its own sensor readings by heating up the thermistor. You can prove this to yourself by doing the following. Plug the unit in from dead cold and compare the readings against a good thermo/hygrometer. Mine is within a few percent...allow the unit for run for a while and you'll notice as time goes on it drifts further and further off reading RH% that are lower and lower until they level off at about 15~20% error (on the low side).
The fix for this would have been very simple, remove the thermistor from the internal circuit board and place it on a cord that dangles from the unit. Unfortunately this is not what they've done. I'm rather tempted to modify my unit as the over humidification is intolerable. The solution given to me by Air-O-Swiss was unacceptable. They told me to turn it off and on as needed!?!?! The whole point of having these fancy electronics is so I don't have to...
In all other regards the unit is very good, low noise, warm mist etc...the automatic aspects of it however are terribly flawed as I've explained above.
Customer Review: It's dead! White dust problem finally solved, but now it has died.
Summary: 1 Stars
I liked this humidifier at first. I had no idea what was causing my house to be so dusty because I purchased the unit on allergybuyersclub.com and the website still advertises "no white dust." I had never had any problem in the past with other humidifiers producing this crazy white dust! Well, once I figured out the humidifier was to blame, I was told over and over it was a HARD water problem by tech support and online research. I have a water softener and visitors to my home report my water is extremely soft (I had it tested later and it is very soft). I had a terrible problem with white dust everywhere within DAYS of replacing the filter, just like another reviewer with a softener, J. VanOrman. Strangely, I also live in Las Vegas, like her! Hmm, maybe weird water here.
So for months I solved the problem by using reverse osmosis water from my filter downstairs. Problem solved, I guess. Expensive filters to buy every 2 months (just to make sure!) and I use my entire tank of reverse osmosis water in the humidifier every 12 hours, requiring 2-3 hours for my reverse osmosis tank to refill (with no drinking water during that time!). Oh, and now I have 2 kids, so I have a new humidifier, too. (NOT the AOS). So now one of them doesn't get humidified air because I don't have enough filtered water to go around. I always pick the sick kid to have the humidified air, otherwise I just try to fill them at different times of the day (like a full-time job some days!)
Now the humidifier is dead. Completely dead after one year of maybe an average of one week per month use. (I didn't use it more than that because I kept trying all kinds of different things to solve the white dust problem!) Now it just won't turn on. Maybe it got so tired cranking out white dust into every orifice of my home that it died. I mean I had to clean out my CD player downstairs and the INSIDE of every cabinet in my kitchen because the white dust was so bad. And it is in my son's room upstairs! Just a horrible experience for me all around. Just picture me climbing 12-foot ladders dragging my vacuum cleaner and hose up there so I could vacuum my curtains covered in visible, noticeable white dust, way up on my wall!
So, white dust solved by expensive filters plus using distilled or filtered water, too. And refill the humidifier every 12 hours. Oh, I forgot to mention, per manufacturer instructions, I placed it at the edge of my son's fine wood dresser. I focused the mist away from the dresser into the room and it caused severe water damage to the wood over a period of time from the mist. Never does it say elevate the humidifier only on a plastic surface to prevent damaging everything with water. Don't most people use these things in bedrooms? All of the bedrooms in my house have wood furniture, and that's the only thing I have to set a humidifier on. And, yes, I did use a little plastic placemat and towel under the humidifier. This damage is in a large area, not from drips but from the actual mist itself. My kid gets to live with the damage for a long time because his furniture is quite lovely and new, so he's not getting a new set for a while. I guess I'll try to refinish the top? That's actually my lowest priority concern with this machine!!
BUYER BEWARE. Other than that, it works pretty well. Oh, wait, it died tonight. It doesn't work at all. And my poor boy has a terrible cold. That is why I took the time to even bother writing this review. I am extremely frustrated.
Customer Review: Huge disippointment
Summary: 2 Stars
There is only one good thing I can say about this - it's quiet. The sound of the steam coming out is very faint, and the gurgles are far and few between. Now, for the bad:
It doesn't work well. The box says it can handle a room up to 650 square feet. Mine can't handle a room that's 200 square feet. When I first turned it on, it said the room's RH was 30, and I set it to the max, and it never got past 40% even though it should get up to 75 with the setting it was on.
Now it won't go above 37 percent, probably because I turned my house's fan on permanently to see if that will help with my humidity because I can't rely on this machine alone.
Second of all, this machine has a poor design with regards to the water storage. When you lift up the tank, there is still water on the bottom half of the machine that is separate from the tank, and it is not enclosed. Spills are inevitable.
Third: I hate when companies make claims without anything to back it up. I don't want them to insist that their silver cartridges are effective, I want a study that can back up how clean the water is when using the cartridge. Just because silver has been historically used to kill germs, doesn't mean that it was effective. There are no studies that prove the use of silver throughout time was effective, so how can you rely on history when it is unproven? And even if it did work throughout history, it doesn't mean that when you put some yellowish silver - ion powder in a plastic cartridge and make a strange looking stick that it will work the same. And hopefully I'm not breathing in silver right now as I am writing this.
Fourth: The value. If this were a twenty dollar humidifier, I wouldn't be surprised at how weak and poorly designed it is, but it's the cartridges that are in the 20 dollar range, not the machine itself. I want to bring this back to Bed Bath and Beyond where I bought it, but I'm afraid that I won't find anything better, since the reviews on humidifiers seem to be very poor over-all. For me, having something quiet is the priority, but it's not important above having the desired humidity, which is why I have a humidifier in the first place. Grrr.
***Update*** It's been about a month and I have some things to add. I bought another humidifier to compare the two (slant fin), and I'm going to stick with this one. It doesn't do a very good job of heating, but it adds way more humidity. I bought a hygrometer online because both humidifiers had different readings on them so I wanted to know what really was going on.
Basically, the hygrometer on it doesn't work at all, just ignore it completely. Now, it can get a 200 sqft room to 46 (according to the good hygrometer I bought), if you give it at least 10 or so minutes, but you can't get things very humid. Ultimately, it's not absolutely amazing, but it's the best one out there and I'll boost it another star just for that.
Customer Review: Best I've ever used
Summary: 5 Stars
I got this to humidify my kids room. Previously we had been using the old vick vaporizer but it only put out for about 6 hours and had some other issues with getting the mineral content of the water just right.
Anyway this is without a doubt the best humidfier I've ever used. Setup was a little confusing at first (where little parts went. The tube hole through the tank was a little disconcerting but after I understood its function I saw it wasn't going to slosh water everywhere.
For a humidfier it has a amazing number of options.
Warm Mist vs Cool
I had always used "warm mist" but my wife wanted "cool mist", this was the only one that had both. Warm and cool are relative terms however. When I think of warm mist I think of the Vicks which can scald you if you get to close. It heats the room up in operation. This device the warm mist is sort of warm. It takes a few minutes to warm up and if you put your hand over the output you can feel its warm but not hot. It goes to warm by pre-heating the water before it hits the vaporizer. In cool mist it just vaporizes.
Output-
You have two output controls, relative humidity and mist volume for lack of a better term. Think of it as fan speed (but no fan)You set the humidity and it spits out water as needed. I don't know where the sensor is but the position of the output nozzel can really affect its reading.
The tank seems to hold enough water for 24 hours of output or 2-3 nights of use. The output is plenty adequate for a bedroom.
Controls-
Lots of controls on/off, heat/no heat, humidity, output, timer, auto mode and more. This is the big difference betwen this and the lower end model. Someone finally figured out how to put a timer on a humidifier (imagine that). So it runs as many hours as you set it. The sleep mode sets all settings automatically and runs 8 hours. I love it.
Noise-
What noise, this thing is silent. No bubbling or hissing or fan noises.
Filling the tank-
Take it out, flip it, unscrew the deminerlization cartridage and fill er up. Not the most stable but it works. Carry handle makes it easy to take back.
Its everything you could possibaly want in a humidifier. Low maintence, easy enough to fill, quite, lots of settings for any need.
Beats the heck out of the old vicks and some fan based whicking mold catching filter units I've used. The closet thing I ever had was a drugstore one that spit out the good stuff for 15 minutes and then broke. This is a quality product (and price) and should last (I've had it 2 weeks at the time of writing). It may be expensive but it does what you want and will outlast many of the others. If you've got the money its worth it.
Customer Review: First Rate Humidifier
Summary: 5 Stars
We bought this unit at Linens N' Things with a discount coupon to use in our bedroom at night. Although we have a humdifier attached to our gas furnace, when we turn the heat off at night, the cold air sucks up the moisture and it becomes hard to breathe. This unit solved the problem.
The unit has quality construction written all over it. The pushbutton controls are logically arranged on the front and the electronic display makes it a breeze to control and monitor both the humidity level(can be adjusted 40-75%) and water level output(five levels). The unit has a handy Auto feature that makes these adjustments automatically depending on the room temperature. I use this feature every night since our room temperature is much colder in the middle of the night. The unit also lets you program it to shut off completely at any interval from 1 to 9 hours. I program it to go off early in the morning when my furnace and main humidifer go on.
I have found that the easiest way to fill the unit is in the bathtub. Simply unscrew the mineral cartridge, turn the tank upside down, and fill it to overflowing. When you screw the mineral cartridge back in, it will elimiminate any excess water, so you cannot overfill the tank. Since the tank is clear, there is never any doubt about how much water is left. Based on my usage, I have found that one full tank lasts me two nights.
A separate gizmo that I have to test the humidity levels in my house confirms that the humidity readings on this unit are accurate.
The unit is whisper quiet. You will not hear any mechanical or gurgling sounds at night(just buy a cheap $30 unit at the drugstore and you will see the difference).
Maintenance requires replacing the mineral cartridge every 2-3 months depending on usage at $12.50 a pop and the silver ion rod that keeps out bacteria each year at $30. Considering the months of comfort that we enjoy from this unit, that's a bargain.
Cleaning the base is easy since it is relatively compact and easily fits under the sink faucet. A symbol lights up on the electronic display to let you know when cleaning is necessary, though you can also easily tell by looking at the base. In any event, you should rinse it once a week with water, and use vinegar if you have any mineral deposits.
This unit provides either warm or cool mist, though we use only the warm mist since that keeps our bedroom temperature from dropping even further. I suggest turning it on about a half hour before bedtime to ensure a warm mist is coming out when you go to sleep since nothing heats instantaneously.
If you want to elimiate stuffy noses in a bedroom or small den, this unit will do the trick. It is not cheap, but it is worth the money.