• CO240
  • Manufacturer has 50 in stock
    This stock is typically available to ship in 3 - 5 working days.



  • Dual display of Carbon Dioxide (CO2) concentrations and Relative Humidity, Temperature, Dew Point, or Wet Bulb
  • Measuring Ranges:
    • Carbon Dioxide: 0 to 9999 ppm with ±75ppm + 5% accuracy
    • Relative Humidity: 10 to 90% RH with 5% RH accuracy
    • Temperature: 14 to 122˚F with ±2.0˚F accuracy
    • Dew Point: -32 to 118˚F
    • Wet Bulb: 12 to 118.8˚F
  • Maintenance free NDIR (non-dispersive infrared) CO2 sensor
  • Audible CO2 warning alarm when concentration level exceeds high user set point
  • Min/Max CO2 value recall function
  • Includes software and cable for on-line (real-time) datalogging to a PC
  • Automatic Baseline Calibration function
  • Data hold and Auto Power Off (with disable) function
  • Low battery indicator
  • Tripod mount (tripod sold separately)

What's in the Box

  • USB cable
  • PC software
  • Soft case
  • (6) AAA batteries


The Extech CO240 indoor air quality meter is an easy-to-use instrument that measures carbon dioxide (CO2), air temperature, and humidity. It also calculates dew point and wet bulb. It is ideal for applications which require monitoring the environmental conditions of an enclosed space such as greenhouse or nursery, to ensure optimal plant grown. It's also convenient for testing the air quality in buildings such as factories, hospitals, conference rooms, schools, and anywhere that high levels of carbon dioxide are generated, to ensure proper air ventilation.

The Extech CO240 indoor air quality meter makes accurate readings which are displayed on the LCD. The user settable alarm with audible beeper notifies users when the concentration exceeds the set point. The CO240 includes software and cable for real-time data logging onto a PC. Other standard features include Min/Max CO2 value recall function as well as Data hold and Auto Power Off (with disable) function.