Product review (3 stars): Precise, but not accurate
Humidity reading is 10% higher than my humidifier's (with built in humidistat) reading. They are right next to each other. Frankly, I don't care if it's accurate, as long as it's consistent/precise, which it appears to be. Once you establish a baseline for what % of humidity you like (based on it's system), the thing is consistent, so it IS a useful device.