Product review (2 stars): Consider Calibration Costs
I am a licensed professional engineer (PE).  I bought the Fluke 971 in August 2013 to check moisture levels on supermarket projects.  This brand new meter consistently reads 2% RH too low when compared to our "reference instrument" [Vaisala HMI41 meter with HMP46 sensor (combined, over $1200) that was calibrated ($275) in August 2013].  The temperature readings appeared to be "spot-on".  The specifications for the Fluke 971 state that it has +/- 2.5% accuracy between 10% - 90% RH.

I called Fluke and asked if my brand new meter could be calibrated under warranty and customer service said, "No".  Customer service also advised that I could get factory calibration for $575!

I also have a competitor's meter (Extech RH390).  This one-year-old meter consistently reads within 0.3% RH of our "reference instrument" (see above).  Further, Extech offers "NIST traceable calibration" for $125.

In a meter like this, calibration of RH sensors is way more important than temp sensors and should be done annually.  Cost of calibration should be a definite consideration when buying a RH meter.