Introduction
The ThermoPro TP157-3 is a compact and highly accurate digital thermometer and hygrometer designed to monitor temperature and humidity levels in various indoor environments. Equipped with a high-performance sensor, it provides precise readings with a fast refresh rate, helping you maintain optimal comfort and health conditions. Its clear LCD display and intuitive comfort indicator make it easy to understand your environment at a glance. This manual provides detailed instructions for setup, operation, maintenance, and troubleshooting to ensure you get the most out of your device.
Product Features

Figure 1: Overview of ThermoPro TP157-3 key features.

Figure 2: High accuracy and sensitivity of the device.
- High Precision and Fast Refresh Rate: Equipped with a high-performance temperature and humidity sensor, offering accuracy up to ±0.5 °C (1 °F) and ±2-3% RH. The device refreshes readings every 10 seconds, providing real-time environmental updates.
- Easy-to-Read LCD Display: Features a clear LCD screen with compact, large digits, allowing for easy viewing of temperature and humidity readings from various angles and distances.
- Face Icon Comfort Indicator: Displays three distinct face icons (DRY, COMFORT, WET) to visually indicate current air conditions, helping you quickly assess and adjust your environment for better health and comfort.
- Versatile Placement Options: Designed with a table stand, a strong magnetic back, and a hanging hole, allowing for convenient placement on any flat surface, metallic surface (like a refrigerator), or wall.
- Long Battery Life: Features a low-power consumption display, extending battery life up to 18-24 months on a single set of AAA batteries.

Figure 3: Understanding the comfort level indicators.

Figure 4: Flexible placement options for the device.
Setup and Installation
Follow these steps to set up your ThermoPro TP157-3 device:
- Battery Installation:
- Locate the battery compartment on the back of the device.
- Open the battery cover.
- Insert one AAA battery (included) into the compartment, ensuring the correct polarity (+/-) as indicated.
- Close the battery cover securely. The display should immediately show readings.
- Placement:
- Tabletop: Extend the built-in stand on the back of the device to place it on any flat surface, such as a desk, shelf, or nightstand.
- Magnetic Surface: Utilize the strong magnet on the back to attach the device to metallic surfaces like refrigerators, metal doors, or magnetic boards.
- Wall Mount: Use the hanging hole on the back to mount the device on a wall using a small nail or screw (not included).

Figure 5: The ThermoPro TP157-3 device ready for placement.
Operation
The ThermoPro TP157-3 is designed for simple and intuitive operation.
- Reading the Display:
The large digits on the LCD screen display the current temperature (in °C or °F) and relative humidity (RH%) simultaneously. Readings are updated every 10 seconds.

Figure 6: Detailed view of the digital display.
- Understanding Comfort Levels:
The face icon on the display provides a quick visual indication of the comfort level based on humidity and temperature:
Icon Condition Humidity Range Temperature Range (for Comfort) 😟 (Sad Face) DRY < 30% RH N/A 🙂 (Smiling Face) COMFORT 30% - 60% RH 20°C - 26°C (68°F - 78.8°F) 😐 (Neutral Face) WET > 60% RH N/A - Switching Temperature Units (°C/°F):
On the back of the device, locate the small button labeled '°C/°F'. Press this button once to toggle between Celsius and Fahrenheit temperature displays.
Maintenance
- Cleaning:
Wipe the device with a soft, damp cloth. Do not use abrasive cleaners or immerse the device in water. Ensure the device is completely dry before re-using.
- Battery Replacement:
When the display becomes dim or stops showing readings, it's time to replace the battery. Follow the battery installation steps in the 'Setup and Installation' section. Dispose of old batteries responsibly according to local regulations.

Figure 7: Battery compartment and expected battery life.
Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| No display or dim display | Low battery or incorrect battery installation. | Replace the AAA battery, ensuring correct polarity. |
| Inaccurate readings | Device placed in an area with extreme temperature/humidity fluctuations (e.g., direct sunlight, near a vent), or sensor obstruction. | Relocate the device to a stable environment. Ensure the sensor vents are not blocked. Allow 30 minutes for readings to stabilize after relocation. |
| Display shows 'HHH' or 'LLL' | Temperature or humidity is outside the measurable range. | Move the device to an environment within the specified operating range. |
Specifications
| Feature | Detail |
|---|---|
| Model | TP-157-3 |
| Temperature Range | -20°C to 70°C (-4°F to 158°F) |
| Temperature Accuracy | ±0.5°C (±1°F) |
| Humidity Range | 10% to 99% RH |
| Humidity Accuracy | ±2% to 3% RH |
| Refresh Rate | 10 seconds |
| Power Source | 1 x AAA Battery (included) |
| Battery Life | 18-24 months |
| Dimensions (L x W x H) | 5.3 x 5.3 x 1.75 cm (2.1 x 2.1 x 0.7 inches) |
| Weight | 140 grams (0.31 lbs) |
Warranty and Support
ThermoPro products are designed for reliability and performance. For specific warranty details, please refer to the warranty card included with your product or visit the official ThermoPro website. If you encounter any issues or have questions regarding your TP157-3, please contact ThermoPro Customer Support:
- Website: www.thermopro.com
- Email: support@thermopro.com
- Phone: Refer to the website for regional contact numbers.
Please have your model number (TP-157-3) and purchase information ready when contacting support.





