# How to test a Carbon Monoxide detector **URL:** \ **Category:** Factual Questions\ **Created:** [September 8, 2010, 2:37am UTC](https://boards.straightdope.com/t/how-to-test-a-carbon-monoxide-detector/553008 "2010-09-08T02:37:46Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![Mama\_Zappa](https://avatars.discourse-cdn.com/v4/letter/m/71e660/32.png) [@Mama\_Zappa](https://boards.straightdope.com/u/Mama_Zappa)\ **Post date:** [September 8, 2010, 2:37am UTC](https://boards.straightdope.com/t/how-to-test-a-carbon-monoxide-detector/553008/1 "2010-09-08T02:37:46Z")
We were awakened by the CO detector chirping “FEED ME”, early this morning. Fresh batteries, and all is well. But this reminded me of a friend whose children nearly died last fall (contractors screwed up the ducting when their house was reroofed) - and their CO detector didn’t go off. Needless to say, she replaced it THAT DAY. So how do we know whether this thing is working? Similarly the smoke detectors. I mean, we can press the “test” button and be sure it makes NOISE - but that doesn’t tell us whether it’ll go off when there is actually smoke. ---
**Author:** ![Una\_Persson](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/una_persson/32/346_2.png) [@Una\_Persson](https://boards.straightdope.com/u/Una_Persson)\ **Post date:** [September 8, 2010, 2:44am UTC](https://boards.straightdope.com/t/how-to-test-a-carbon-monoxide-detector/553008/2 "2010-09-08T02:44:31Z")
My Sentry Night Hawk recommends lighting a match nearby and blowing it out, blowing some smoke on the detector, or else doing the same with a candle. Usually you will be amazed at the high level of CO it will read from doing this, like in the hundreds of ppm. ---
**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\ **Post date:** [September 8, 2010, 3:18am UTC](https://boards.straightdope.com/t/how-to-test-a-carbon-monoxide-detector/553008/3 "2010-09-08T03:18:09Z")
sensing element on CO have a 7 year life. i think smoke alarms have a 10 year life. ---
**Author:** ![Mama\_Zappa](https://avatars.discourse-cdn.com/v4/letter/m/71e660/32.png) [@Mama\_Zappa](https://boards.straightdope.com/u/Mama_Zappa)\ **Post date:** [September 9, 2010, 2:10pm UTC](https://boards.straightdope.com/t/how-to-test-a-carbon-monoxide-detector/553008/4 "2010-09-09T14:10:33Z")
Thanks! We’ll try the blown-out candle trick (wearing ear protection… I have this mental image of the damn thing going out so loudly that it startles me, causing me to fall. The CO detector is at face height but the smoke detectors are high enough that we’d need ladders to reach them… ---
**Author:** ![kevinlai](https://avatars.discourse-cdn.com/v4/letter/k/73ab20/32.png) [@kevinlai](https://boards.straightdope.com/u/kevinlai)\ **Post date:** [September 6, 2013, 10:41pm UTC](https://boards.straightdope.com/t/how-to-test-a-carbon-monoxide-detector/553008/5 "2013-09-06T22:41:03Z")
People die when they leave the car engines on and close the garage door. You can test your Co2 alarm by putting on the end of your exhaust car ---
**Author:** ![Hail\_Ants](https://avatars.discourse-cdn.com/v4/letter/h/dc4da7/32.png) [@Hail\_Ants](https://boards.straightdope.com/u/Hail_Ants)\ **Post date:** [September 6, 2013, 10:45pm UTC](https://boards.straightdope.com/t/how-to-test-a-carbon-monoxide-detector/553008/6 "2013-09-06T22:45:43Z")
> [@kevinlai](#): > > People die when they leave the car engines on and close the garage door. > You can test your Co2 alarm by putting on the end of your exhaust car I think there’s a warning on the boxes to specifically \*\*NOT \*\*do this. Don’t know if its just to prevent idiots from killing themselves accidentally, or if it will damage the unit’s sensors. ---
**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\ **Post date:** [September 6, 2013, 11:48pm UTC](https://boards.straightdope.com/t/how-to-test-a-carbon-monoxide-detector/553008/7 "2013-09-06T23:48:11Z")
> [@kevinlai](#): > > People die when they leave the car engines on and close the garage door. > You can test your Co2 alarm by putting on the end of your exhaust car zombie or no you aren’t testing for CO[sub]2[/sub] you are testing for CO. giving a large dose of CO and other stuff in auto exhaust could poison (ruin, break) the detector. ---
**Author:** ![AaronX](https://avatars.discourse-cdn.com/v4/letter/a/7bcc69/32.png) [@AaronX](https://boards.straightdope.com/u/AaronX)\ **Post date:** [September 7, 2013, 3:02pm UTC](https://boards.straightdope.com/t/how-to-test-a-carbon-monoxide-detector/553008/8 "2013-09-07T15:02:47Z")
> [@kevinlai](#): > > People die when they leave the car engines on and close the garage door. > You can test your Co2 alarm by putting on the end of your exhaust car Guys, he didn’t finish the post. I don’t think his alarm’s working. ---
**Author:** ![Malacandra](https://avatars.discourse-cdn.com/v4/letter/m/45deac/32.png) [@Malacandra](https://boards.straightdope.com/u/Malacandra)\ **Post date:** [September 7, 2013, 6:39pm UTC](https://boards.straightdope.com/t/how-to-test-a-carbon-monoxide-detector/553008/9 "2013-09-07T18:39:30Z")
I never bother with one - I count on detecting the horrible rotten-egg smell long before the CO concentration reaches lethal levels. Wait, though, isn’t that hydrogen sulf ---
**Author:** ![Rick](https://avatars.discourse-cdn.com/v4/letter/r/9f8e36/32.png) [@Rick](https://boards.straightdope.com/u/Rick)\ **Post date:** [September 7, 2013, 7:20pm UTC](https://boards.straightdope.com/t/how-to-test-a-carbon-monoxide-detector/553008/10 "2013-09-07T19:20:20Z")
> [@kevinlai](#): > > People die when they leave the car engines on and close the garage door. > You can test your Co2 alarm by putting on the end of your exhaust car Modern cars often have CO levels that are amazingly low. Now a 62 Buick on the other hand would probably produce 10% CO. ---
**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\ **Post date:** [September 7, 2013, 7:46pm UTC](https://boards.straightdope.com/t/how-to-test-a-carbon-monoxide-detector/553008/11 "2013-09-07T19:46:45Z")
CO is odorless which makes it extremely dangerous.