This is by far the longest, most detailed review that I have ever written for a product. But, I would like people to know what to expect from this unit, and to learn a bit about humidity and what affects it. So, here we go. OK, I've read at least 100 reviews of different humidifiers on Amazon and other sites before I settled on buying this unit. And, I'm glad -- and sad -- that I did. MOST negative reviews come from people whose expectations can not be met by any humidifier currently on the market. There are undoubtedly bad humidifiers out there, but this is not one of them. Also, some people buy a product with unrealistic expectations as to what that product will actually do, or what care it will require. This is unfair to the product, although the makers do put out some fantastic claims without giving us all the background necessary to understand the claims. So, what are some of the unrealistic expectations I see people complain about? I'll address a few here and give my view of them. (1)The humidifier should make absolutely no noise whatsoever. Really? If the unit operates on electricity with some part that moves, you WILL get some noise - period. How much is dependent on how fast those parts move and/or the type of movement. In the case of this humidifier, it has 3 fan speeds, and off. On the lowest fan setting, placed on a carpeted floor 5 feet from our bed, you can not hear the fan on low. On medium speed (which is where we keep it to sleep), you can hear it a little when you are awake, but it does not keep us from getting to sleep or staying asleep. On high speed, where it will humidify a room the fastest, you can definitely hear it, and we can not sleep with it at this speed. On the lowest speed it will not raise the humidity very much. We use high speed only in the daytime to humidify the air and objects in the room as much as possible. In addition to the fan, you will have the occasional gurgle of water from one of the plastic jugs as it refills the reservoir as water in the reservoir gets evaporated away. Want to know what that sounds like before you buy? Fill a gallon plastic milk jug with water, then pour it out faster than air will enter the jug opening. You will hear and see the water glug and gurgle as the air enters behind the water that empties. Our unit does not "glug", it "gurgles" (a softer sound for only 3 or 4 seconds). If this wakes you from a sleep, then you a VERY light sleeper, you have the unit on a sound resonating object (like a hard nightstand or wooden floor), or it it simply too close to your bed and at too high a height. Try placing it on the floor on a carpeted surface away from your bed. You'll be amazed at what a difference in noise level this makes. 2) The unit should require absolutely no maintenance. REALLY people, do you ever buy anything that requires no maintenance? Do you run your car without doing maintenance on it? What you WILL have to do to keep this humidifier operating in tip-top shape are the following: (A) Refill one or both of the plastic jugs that supply water to the unit as they get used up (evaporated). The jugs have a handle on one side, and are flat on the other side. I lay mine down in a laundry sink, aim the spout over the opening, and then fill it. It takes exactly 1 minute and 15 seconds for me to fill one of the 2 gallon jugs in this fashion (once it is positioned in the sink). 2 gallons is a lot of water, and it weighs16.72 pounds. So count on having to carry that much weight with the handle provided on the jug if you fill it all the way. Can't carry that much weight? Don't fill it all the way! I bought a bottle of the BestAir Humidifier Bacteriostatic additive to put in the water. I don't know if it works or not, as I have always used it, and have no problems with algae so far. I gave up measuring capfulls of the product, and just guess at the amount as it can't be rocket science. It does NOT prevent my water softener softened water from building up as a deposit on the filter (see B below). The jugs tip into place extremely easily whether the top is on the unit or off the unit. They never spill for me. Do NOT try to tip them slowly -- just set them against the unit at the bottom, and tip them quickly upward into place. Nothing to it. You can remove them one at a time, with the top on the unit, even if the other jug still has water in it. This is a nice feature, as you can simply refill the unit one jug at a time. You can even remove a jug that still has some water in it without any of it spilling out. (YES, for "safety", I keep an aluminum baster/roaster under the unit in case any water were to spill out, but to date none ever has.) B) The filters (they are really wicks) will develop a crusty edge at the top on the outside portion after running a few days. In my case, this is due to my water softener water that I use. I never tried store bought water as my water works just fine in the unit. Whatever water you use, if it has ANY impurities in it, regardless if you can see the impurities or not, then you WILL get a residue on the wicks as the water evaporates. Where else would these impurities go? A pan of water on the stove that is evaporated will also leave behind the same impurities! To ameliorate this issue, I simply turn the wicks upside down and over every other time I fill the jugs! That is, if the yellow/tan buildup is on the top edge outside, rotate the wick until that edge is on the bottom to the inside of the unit. It will re-soften and disappear (only to reappear on the top edge outside later). Then, once a week, or whenever I feel like it, I take these wicks out, take them to my laundry sink, lay them flat on the bottom, fill the sink until the water is about 1" over the top of the wicks, then add a cup of white vinegar. Let the wicks soak in this for about an hour, rinse them in clean water, stand them against inside of the sink on edge to drain and then reinstall them in the humidifier. Voila, the vinegar dissolves the salts that have accumulated, and rinsing them flushes them away. At the same time, I empty out the reservoir of the unit and flush it well with clean water. It is like starting over again. This process takes maybe 15 minutes of time to do once a week or so. BE CAREFUL WITH THE WICKS, as they are easily destroyed. Handle them gently, NEVER try to wring them out or press dry, just stand them on edge against the empty sink when you are done for about 20 minutes, and they will drain on their own. I did buy a second (spare) set, but after 3 weeks, I have not even taken them out of the package. I see no reason why the wicks won't last at least 2 months with proper care -- maybe even a full winter season. C) Other maintenance? I don't know of any, but then I haven't had my unit except for 3 weeks. An old adage my father taught me: It is far easier to spend a little time keeping something clean and operating well than to have to repair it due to neglect. It is true.So, how well does it work, and what is my environment like? First, I live in a 2 story house, with a bedroom and large living room that have very high cathedral ceilings. My bedrooms are all carpeted, and most of the main house (foyer, dining room, dinette, kitchen and laundry room) are tiled. I bought the humidifier to raise the humidity in our master bedroom at night to alieve mild symptoms of difficulty breathing, and getting some blood in our noses at night. It WORKS for doing this. Based on the hygrometer readings, the unit keeps our bedroom (15' x 20') and attached master bath and master closet a full 8% relative humidity higher than in the rest of the house. This despite the fact that we have central heating with LP gas that disperses the air from the bedroom into other parts of the house when it runs (even with the door to the bedroom closed). Hence, some of the additional humidity gets distributed to the rest of the house through the heating system. Note, if you turn your heat down at night (we turn ours down 10 degrees at night), then the bedroom with the door closed will be sealed off from the rest of the house and humidify more quickly until the temp drops the full 10 degrees and the heating system kicks back in. This 10 degree drop also helps increase the relative humidity level at night because cooler air holds less real moisture than warmer air; hence, with the same amount of water in the air, the relative humidity goes up until that water vapor gets absorbed by other things. Note that I just mentioned that water vapor gets absorbed by things. Those things include anything that is soft, including carpeting, bedding, blankets, pillows, wood (Yes, wood does absorb moisture), drywall, etc.. My point is that when you start up any humidifier, all of the objects in the space are very close to the same relative humidity as the air in the room. As you try to increase the relative humidity in the room, the "soft" objects will absorb this same moisture. So, you are humidifying NOT ONLY THE AIR, but all soft objects in that room. That takes a LOT of water to move the relative humidity a little bit! So, do NOT expect ANY humidifier to instantly raise your humidity level any appreciable amount quickly. It will rise slowly, but should rise consistently unless you have a lot of air leaks in your home. In my case, my unit with outside air at about 32 degrees and inside air kept at 60 at night, 70 in the daytime keeps my bedroom at a full 8% relative humidity increase over the rest of the house (53% in the bedroom versus 45% in the rest of the house). That's pretty damn good in my view, and helps us tremendously in sleeping. It also helps any valuable furniture you might have in that room. About the built-in humidistat in this unit. It does work, but as has already been pointed out, there are no settings etched or printed into the dial. If you turn the dial all the way up, the unit will run constantly without ever shutting off. This is for all intents and purposes an "infinite" (100%) setting. After humidifying your room for about a week, try turning down the dial slowly with the unit running. It will likely turn off at some point. Whatever your relative humidity level is in the room, this is the point on the dial where this humidity level will be maintained. If you have a separate hygrometer to read your relative humidity level (I bought the ThermoPro TP50 unit which works very well), then you could mark the dial on your Vornado humidifier with this number to get some relative point of reference for the future, but don't count on that setting continuing to be accurate. Want more info? Check out the photos that will show you that this is a SIMPLE machine with only 6 parts: A top half that contains the fan and all the controls, a bottom half which is nothing but a molded plastic tray that acts as a reservoir to hold the water, 2 wicks that rest against the outside slated portions of the bottom with one edge sitting in the water, and 2 plastic 2-gallon jugs that provide the water to be evaporated. All parts simply slip-fit together without use of any screws, pegs, nails or anything, and they stay together well. Very easy to lift each part away. NOTE: When this unit has water in it, do NOT attempt to pick it up and move it, as it can and will fall apart since all parts simply slip-fit together, and the water is HEAVY. The top can be lifted off without unplugging or turning off the fan, and set aside, as it is self-contained. This reveals the 2 water jugs on either end, and the 2 wicks in the center. Easy as pie! In the photos you will see the hardened residue that I get on the wicks after 4 gallons of water have been evaporated. I have already turned one of the wicks over and around and put it back in one of the photos, which is why it shows on the inside bottom, rather than the outside top where it actually accumulates from the drying action of the unit. How fast does it evaporate water for me? Remember, I'm starting at about 45% relative humidity (not too bad), so the water does not evaporate that fast at this high a humidity level. The unit on medium will evaporate about 2 gallons of water a day into my bedroom raising that humidity level to 53%. If I kept my temperature higher, and/or my air was drier to start with, then the unit will evaporate water into the air at a faster rate. Remember, it is RELATIVE humidity, not absolute moisture in the air that you are measuring. Good luck with your unit, and sleep/live well!