Experiences sought with handheld CO monitor/alarms

I’m seeking an update on CO meter experiences (the archives have some older material of older models). What works for you?

I see out there:

  • Molex/Sensorcon $129. Two year battery. Two year sensor life, not replaceable. Not a personal safety alarm.

  • Extech/Flir CO15 $155/inspector outlet. AAA batteries. Unspecified life of sensor.

  • dSense portable. $69/gaslab. Looks just like the CO15. 1 year warranty.

  • Klein Tools ET110 $96/home despot. Five year sensor life. Not replaceable. 20 minute unattended measuring limit. 4xAAA

  • Fieldpiece SCM4. Replacement sensor RCM4 $159. Two year sensor, factory calibrated.

  • Teledyne Protégé ZM . Two year life on or off. $93. Pre-calibrated.

  • Forensics Detectors - Assorted “World’s best gas meters”.

The differences seem to be:

  • Battery policy: 24/7 or ON/OFF
  • Sensor lifetime
  • Ability to replace a sensor
  • Response time
  • Personal safety alarm or not
  • Calibration
  • Physical size and battery type

I’m unclear if the ON/OFF models are really measuring sensor lifetime correctly.

I had used the Fluke CO-220 for years until the display went out this year. I was going to replace it with another one until I saw the price, >$500.00.
I bought the Klein ET110 to replace it and it seems to work just as well.


I’ve been using one of these for over six years and it is still working:


The sensorcon says that after 2 years it will read END of life, and if recallibrated will go for another 180 days. True?

I read a few Amazon reviews. It appears to be outsourced by Klein, and problematic

My PRO sensorcon has been working for Six years and has never read end of life. It picks up the most minute amount of CO. I found that it will also detect (not by design) Hydrogen Sulfide.

I’m looking at the
Model: FD-90A-CO

Because the company seems to be enthusiastic about gas meters, and the sensor is replaceable. The electrochemical sensors wear out over time, so being able to freshen it up is attractive.

(I think all of them Hydrogen Sulfide triggers them as well)

Klein et110 co meter. Works great.