I have purchased two MistAire Eva4-Speed Evaporative Humidifiers and have been using them since November of last year. I am very satisfied with the performance of these humidifiers. Especially, when there is a strong need for humidification, the indoor environment quickly becomes moist when set to maximum performance. I use it on the second level at night, and it is very quiet and pleasant. I refill the water about three times a day and am very satisfied with its performance.