Review on Long-Lasting Protection: Kidde 21010047 C3010D Carbon Monoxide Alarm with Digital Display and 10 Year Sealed Battery by John Clark

I bought this because our fireplace sometimes has a draft and I wanted to make sure the CO levels never got dangerously high. This device seemed decent enough to me when I received it. As soon as I put the back cover on, it immediately came to life with a loud beep (test) and then a zero appeared on the LCD. Zero stayed there. And he stayed there for some time, firm and imperturbable. That should be reassuring, right? Well, I don't know about you, but I'm not one to take things for granted without evidence, especially when it really matters (like life and death). I can easily test my smoke alarm, why not use this 'carefree' carbon monoxide kiddie alarm? After learning that the meter reads zero unless it detects CO above 30ppm (or registers a peak above 11ppm), I thought I'd have to test it where the concentration of carbon monoxide is decently high. I went to my car, started it and held it just behind the exhaust for a good minute. Nothing. Still zero on reading and still zero on detected peak (meaning never more than 11ppm detected). I'm no expert but I would guess that the exhaust should be above 11ppm even at idle. I plan to investigate this further. I will update the information as soon as I know more about it. Update After further research I found some correct methods to test carbon monoxide detectors. The test really needs to be done indoors. The easiest way is to take a large pot with a lid (like a saucepan), place an alarm clock and a lit candle inside, and close the lid. After about a minute, the candles will use up all the oxygen and release the CO. go out. In my case, the alarm set a value of 50 after about a minute. It works out.