Not impressed

I've been looking for a decent humidifier for a while now and I've always had bad luck. After going through several different brands and being disappointed I decided to spend a bit more and get this unit based on the good reviews. I got it home and was initially impressed by the machine's output and the digital readout on the front. I left it on and waited for it to reach the desired humidity of 50%. And I waited. And waited. After a week of running it near constantly the humidity in my bedroom never managed to get above 35% and the air felt just as dry as always. As far as I could tell, the unit did nothing but spit out mist with no other noticeable effect. So I tried moving it into my office to see if maybe it would perform better in a smaller room. It did. After a while I got it to reach 50%. I took it back into my bedroom and once again, the readout remained under 30% and the air remained dry. Apparently my bedroom, which is only 180 square feet, is too big for this unit to handle. Strange since the stats claim it can humidify an area up to 600 sq ft. Then to top things off, after three weeks the unit began coating my bedroom with white dust! The filter is supposed to last 2-3 months and mine needed replacing after less than one! And those filters cost $20 at the store! $170 for a humidifier that doesn't humidify and an estimated $250 a year to maintain it is not my idea of a good deal. I packed it up, took it back to the store and got a refund. This product is not recommended.