Product review (1 stars): Inaccurate unit
I have bought 4 of these from Amazon. I have calibrated all four for temperature accuracy and they all consistently read the same within acceptable limits.  However, with one of the units I cannot adjust the relative humidity.  I cannot correct the humidity reading with the adjustment. The dew point reading depends upon the accuracy of the relative humidity and so the dew point is in error.  I need a good dew point reading to prevent mold in some air handling equipment so this unit forces me to guess on its error and estimate the dew point.  Not a good feeling.  Some people might think three out of four is not bad but I don't see why I have to put up with the time and trouble caused by poorly manufactured and tested products!  One star, less if I could!