air quality Devices

Protmex PTH-5

Yet another highly portable standalone CO2 Meter. This one with great battery life. One of the recommended devices. It is not absolutely flawless but is ok to buy. It got fast, accurate, and low power t/RH sensor (Sensirion SHTC3). Its CO2 sensor is kind of average (Cubic 1106 probably). Charging 5v 1A


  • 2400 mAh battery (~20 hours of battery life)
  • Small and relatively lightweight (8x3cm, 145g)
  • Calibration can be done manually
  • Correct t/RH during normal operation


  • Leading zero in CO2 display
  • CO2 measurements might sometimes be wrong
  • CO2 measurements delay is on power on
  • CO2 measurement interval is 16/4 sec (10 sec average)
  • t/RH measurements during charging is a bit incorrect
  • Display view angles are not perfect

Device inside

AliExpress Price: ~60$ (may change)

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