Therm Pro Vs. Secrui: Which Hygrometer is more accurate?

Over the last few weeks I monitored the differences between 3 different Hygrometers.

• ThermPro TP50

• ThermPro TP49

• Secrui TH1

I found that overall that the ThermPro TP49 and TP50 hygrometers held the closest accuracy to the scientific Extech Psychrometer RHT510(Trusted/control variable Hygrometer) used by professional piano technicians in the field. (Read more about the Extech)

The ThermPro TP50 (as long as it was standing vertically, reads with the greatest accuracy, while also showing the highs and lows of the temperature and humidity over long periods of time.

Whereas, the Secrui TH1 never gave an accurate humidity reading. The temperature was the only accurate metric this hygrometer had.

ThermPro 50

Buy ThermPro 50

Here's the ThermPro 50 that yielded the most accurate results throughout my observations.

As long as the hygrometer was propped upright (on it's little kick-stand) it's properly measuring the ambient humidity as well as temperature.

ThermPro 50

I covered up the emojis that this device provides in the upper right hand corner. This is because the emojis tells you if the humidity is in the "comfort-zone." Unfortunately, the comfort-zone doesn't accurately represent what is an ideal temperature and humidity for pianos, so I decided to block it out with some blue stick-e notes.

Hygrometers

Here I have all of the hygrometers I tested for this experiment. The green hygrometer on the left hand side is the most accurate that I measured the less expensive hygrometers against.

Almost right away, I could tell that the Secrui TH1 didn't have accurate humidity readings.

The ThermPro's (while not always 100% accurate) were closest to the scientific Extech Psychrometer RHT510.

Outdoor hygrometer comparison

As you can see, the ThermPro on the right hand side displayed a humidity that was far-off.

The main reason that this hygrometer was inaccurate in this photo is because it was laying down on the ground where the sensor is resting against the humid wooden patio.

ThermPro 49 Hygrometer kick-stand

As you can see, the hygrometer is standing on its built-in kick-stand so that it can properly measure the ambient humidity.

Be sure that when using the hygrometer it is standing upwards so that you don't get any false readings.

The ThermPro 50 also has a kick-stand so that it can track the most accurate temperature and humidity readings in the room.

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ThermPro 49 on its back

Here's an example where this hygrometer may provide false readings because it is laying down on its back.

It's necessary to have the hygrometer stand on the kickstand so that it can give the most accurate reading.

The Secrui TH1 Hygrometer Review

While the Secrui may be able to read temperature accurately, the humidity reading is not calibrated accurately and so displays false readings.

This device cannot be trusted for home humidity readings.

Many people have purchased this hygrometer, though the readings are inaccuratetely calibrated, and are not to be trusted.

That's it! I hope you enjoyed this simple comparison article.

If you're going to go with an inexpensive hygrometer, I would choose the ThermPro 50. Though, the ExTech Psychrometer RHT510 is the best on the market.

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