Product review (2 stars): VERY slow response
I am not at all happy with the response time of the outdoor sensor.  I did a test: I put the sensor in the fridge until it read 40 deg. F.  Then removed it, sat it next to the base unit, and waited til it reached room temperature.  It took OVER AN HOUR and still did not make the last step from 75F to 76F (the reading on the indoor sensor)!  For the technically inclined, I measured the 1/e time constant to be 18 minutes. The specs say the outdoor temp is updated every 30 sec, but that's meaningless if the sensor responds so slowly.  Very disappointing.  It's going back to Amazon.