My wife gets sick a lot. She has a very low immune system, she gets pnemonia and bronchitis a lot. She has asthma and is just a wreck! I love her though and wouldn't change her for anyone else. All this being said, we have gone through a lot of medications, cold and doctor visits. Our insurance is Kaiser and the last doctor told her that in order for her to stay healthy longer she needs to have moist air. The dry air isn't good for her. I have no idea why not, but there you go.
We have been told this before, but to only use when it she had a cough or bad cold with her lungs or asthma attacks. We have been married for six years and have been through probably ten different humidifiers. All different brands, all different price ranges. Ones with night lights and cutsie things, one that were hot air, cold air, smelly air. I thought they were basically all the same, she did not. Now I know because this last one we got is awesome.
It is made by Vicks. This is not our first Vicks brand, but this one far outweights the $60 one we got last time that we threw in the trash! This one has a high and low knob. Also off. It has a small green light to tell you that it's on because the low is very quiet and you can't hear it. It has a great top compartment that lifts off and you can carry it to the sink and easily fill it and place it back. The water tank is large so you only have to fill it about every three days when you have it on high so if you were using the low probably only about once every week and half or so. They are dishwasher safe.
So, does my wife still get sick...yes, but she gets better quicker it seem so it must be working! And ease of use, clean up and function this is the best we've ever had...and we've had a lot. Take it from me, I am basically an expert on this.