Product review (5 stars): Very sensitive instrument!
Let me say that I do like FLUKE products, I always trust FLUKE when it comes for all my digital multimeter or a multitester needs. I have been using my Digital multimeter at work & home for years and has never failed me. When I was offered to review this handy industrial grade FLUKE 971 Temperature and Humidity sensor I gladly accepted it trusting that it will be accurate and will provide years of service.

The unit came with four AAA batteries installed and the temperature setting to degrees Fahrenheit. You can change the switch to read degrees centigrade if you wish also you can disable the auto shutoff feature. These buttons are accessible inside and adjacent to the battery compartment. This meter also has back-lit LCD display and the readings were easy to read. Pushing the power button automatically starts the humidity and temperature reading instantly.

Now, I am not a licensed contractor nor I repair HVAC epuipments but I do see the need for accuracy where the industry demands it. From my observations right out of the box the unit was very accurate but there is always a chance for these meters to go out of calibration as some of the reviewers have mentioned here. The accuracy of 'RH' is the key, yes these meters can get off calibration especially when subjected to extreme changes in temperatures and humidity you need to give the meter few mins for it to acclimatize to the environment you are trying to get reading from.

This is not your grandma's temperature probe. This is a very capable sensitive instrument which built to last. This is an industrial grade unit, built to take a beating! IMHO much quicker than a sling psychrometer and Yes, it does respond slowly which is the nature of thermo-hygrometers so before you say it is slow to respond thing again what you are using it for and you will see that it will provide faithful readings.

Also, if you do not use the instrument for a long period, the meter can 'dry-out' causing the inconsistent readings that some reviewers have mentioned here. Cycling in a humidity chamber for few days at 90%+ humidity and 20C/68F to 30C/86F can often bring a dried-out meter back into factory calibrated specifications without having to spend a tons of money on factory calibration cost.