Review on 🌡️ D'Addario Hygrometer: High-Performance Humidity and Temperature Sensor by Matt Kim

I bought two of these in cases for my three acoustic guitars. I had a Planet Waves oval hygrometer that I had previously bought for one of the guitars and decided to buy two more for the other guitars. All three guitars are stored in cases with a Planet Waves humidifier. I noticed what I think is a big difference between the three units, so I put all the hygrometers in the same place in a guitar case. There was still a lot of variety, so I left them next to each other on the table overnight and checked again in the morning. The readings were 28%, 31% and 34%. This is a quote from the Planet Waves website about these devices "accurately displays temperature and humidity readings". The device with the highest value is 21% higher than the device with the lowest value. I think "exactly" is closer to 5% spread in my opinion, and certainly no more than 10% spread. If the mean is the right value, you get +/- 10% accuracy, but hardly. If the average value is not correct, one of the blocks has an error of more than 10%. Of course, Planet Waves does not list device accuracy percentages on its website or in product descriptions. Just the quote above. When I only had one oval hygrometer (which was also the tallest of the three) I assumed it would give me accurate readings. Now I don't know what is right or closest to right.