• Innovative graphical display shows the measured humidity values of the last 24 hours like a radar screen
  • Large, easy-to-read LCD displays % Relative Humidity, Indoor Temperature and Dew Point
  • Measurement ranges:
    • Humidity: 10 to 99% RH
    • Temperature: 14 to 140°F (-10 to 60°C)
  • Basic Accuracy:
    • Humidity: ±4% RH (30% to 80%), ±5% RH (other ranges)
    • Temperature: ±1.8°F/1°C
  • Beeper sounds and bright LED flashes when humidity level exceeds 65% RH
  • Facial icons indicate comfort zone (between 40 to 60% RH) and uncomfortable zone (under 40% RH or over 60% RH)
  • Stores and recalls Max/Min readings
  • Desktop stand can be removed for wall mount use

What's in the Box

  • Stand
  • 2 AA Batteries


The Extech RH35 hygro-thermometer monitors humidity, temperature, and dew point for the previous 24 hours and alerts users to indoor mold hazard conditions. An innovative graphical display shows the measured humidity values like a radar screen. The RH35 alerts users to humidity levels that are too high or too low. A frown icon warns when humidity reaches 60% RH. When the RH exceeds 65%, a loud audible alarm and bright flashing red LED will be triggered. The frown icon will also appear if the environment is too dry (under 40% RH) where static electricity becomes a concern.

The Extech RH35 hygro-thermometer is ideal for applications for commercial, retail and residential sites prone to mold such as laboratories, R&D, server rooms, clean rooms and bio-pharmaceutical manufacturing areas. It is also for use in area where monitoring for humidity is paramount including museums and storage and document archive facilities.