Klein ToolsET110 CO Meter, Carbon Monoxide Tester and Detector with Exposure Limit Alarm, 4 x AAA Batteries and Carry Pouch Included

I had several propane leaks in a new house that we moved into. I bought the gas sniffer from Klein which was great. At that point I wanted to make sure nothing else was wrong. So I bought this. To test it I tried it in another house that had a ventless propane fireplace. Once i turned the fireplace on it registered a slight increase in CO2, but well within an acceptable range. It brought peace of mind to my wife which makes it priceless!

I bought this because we have had 2 CO alarms go off at like 10PM, which is no fun. Yup fire dept and local natural gas tech had to show and clear our house of CO leaks, BEFORE we could get back in our house.Turns out our gas fireplace had glass chips in it - something great new idea apparently - but they we covering up the air slots in the interior of the gas fireplace. So the CO was being kept down inside the fireplace, instead of pulling in the fresh air from the house.Once I removed the glass chips it did fix the problem!!! But I wanted to be sure and not get the opportunity to be stuck outside again! Thanks to a local fireplace install company!I kept the Klein CO sensor running for a couple of hours and no CO!!!

Appears to work as expected.Reports zero when in clear air.Reports over 300PPM when placed about 4ft from UTV exhaust (it's a 20 year old gas engine).The response time was 2-3 seconds 4ft from gas engine exhaust and readings zoomed over 300ppm and I moved away. Real world quick test appears to work.I tested our home air ducts in several places with this meter and all of them read 0.We wanted to put a number to CO ppm in addition to the smoke detectors with CO detection which always show OK without any numeric value. Having a good quality meter seems like a wise idea if you have natural gas or propane heating. I am happy with the unit after one use.Note: If you are a home owner and not likely to use the meter very often, consider removing the AAA batteries after each use so there is no chance of a battery leaking into the meter.

I work in HVAC and use this CO meter daily. I wish the auto shutoff wasn't so fast, because each time it shuts I go outside to zero it and come back inside. I also wish it had a magnet on back possibly instead of the pocket clip, but that is probably just preference. Overall works well and battery lasts a long time.

Was monitoring CO from my old gas furnace through winter from time to time

we had our AC/heater unit inspected, they guy turned on the furnace and measured carbon monoxide with his unit and claimed he read 13ppm, and already sent us a quote for 15k to change the furnace to a new one. We were a bit shocked of course. We decided to double-check it ourselves and got this unit. We got it and, first of all, I wanted to make sure that it actually can detect carbon monoxide. We made sure to follow the instructions and we even turned and unit on and did the self-calibration (set button) outside, to make sure that it is calibrated in a space without any carbon monoxide. To get a positive control I lit a candle and blew it out. That first moment after a candle is blow out and you see a smoke, there is definitely some carbon monoxide forms. And, indeed, the unit went off. Showed something like 150 ppm (I put the meter right where the smoke from the candle was). In the rooms the reading was just zero. I was repeating these measurements in the rooms to make sure it is still zero, and it was. One time when I was messing around with it, I decided to breath on it just for fun, and it measured 3 ppm of carbon monoxide. I didn't know whether human breath supposed to have any, so I googled it and I saw that human breath for non-smoker should have 1 - 6ppm carbon monoxide. That was a cool observation, because it meant that the unit is indeed sensitive. So, since it so far looks that the unit is capable of measuring high (candle) and low(breath) amounts of carbon monoxide, and it still shows 0 ppm in our rooms, I think we won't be spending 15k for new furnace for now.

I was feeling sick and couldn't figure out why, so I brought back out my air quality tester (that is now in the garbage), and it signaled to me that the CO was extremely high in my room, scared the crap out of me, got this overnighted to me, turns out the cheap Chinese air quality tester has a tendency to be completely WRONG. Keeping it around in a drawer for future use, but this thing is awesome, well built and seemingly very accurate.

Klein tools work as they should.