Product review (1 stars): Very inaccurate -- reads WAY too low!
My experience is similar to several of the one star reviews -- it is not accurate and consistently reads much too low.  I became suspicious when it was consistently reading a bedroom humidity of 10%, even after i placed a room humidifier about 6 feet from the unit.  I then took it outside and placed it on our porch -- it actually was raining and the national weather service reported local humidity of 89%.  After an hour the gauge read 15%.  Save you money.  Only positive I can say is I only wasted about $9.