# Why are my Smoke Detectors beeping? **URL:** \ **Category:** Factual Questions\ **Created:** [December 23, 2007, 11:24pm UTC](https://boards.straightdope.com/t/why-are-my-smoke-detectors-beeping/431065 "2007-12-23T23:24:09Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Sub\_Judice](https://avatars.discourse-cdn.com/v4/letter/s/ba9def/32.png) [@Sub\_Judice](https://boards.straightdope.com/u/Sub_Judice)\ **Post date:** [December 23, 2007, 11:24pm UTC](https://boards.straightdope.com/t/why-are-my-smoke-detectors-beeping/431065/1 "2007-12-23T23:24:09Z")
I have 2 mains-powered Smoke Detectors in my house that make a regular ‘chirp’ if the backup batteries are low. I’ve replaced the batteries in both with brand new Duracells, checked the main circuit breaker isn’t tripped, and I’ve vacuum-cleaned the sensors, as I’ve heard that can confuse the little buggers. Any suggestion, pilgrims? (Plan B may involve a large hammer, extreme violence and a misguided sense of my superiority over inanimate household fixtures) ---
**Author:** ![Hanna](https://avatars.discourse-cdn.com/v4/letter/h/b3f665/32.png) [@Hanna](https://boards.straightdope.com/u/Hanna)\ **Post date:** [December 23, 2007, 11:27pm UTC](https://boards.straightdope.com/t/why-are-my-smoke-detectors-beeping/431065/2 "2007-12-23T23:27:03Z")
Are they strictly smoke detectors or combo smoke/CO2 detectors? Maybe your CO2 levels are up… ---
**Author:** ![Sub\_Judice](https://avatars.discourse-cdn.com/v4/letter/s/ba9def/32.png) [@Sub\_Judice](https://boards.straightdope.com/u/Sub_Judice)\ **Post date:** [December 23, 2007, 11:29pm UTC](https://boards.straightdope.com/t/why-are-my-smoke-detectors-beeping/431065/3 "2007-12-23T23:29:07Z")
[QUOTE=Boscibo] Are they strictly smoke detectors or combo smoke/CO2 detectors? Maybe your CO2 levels are up… [/QUOTE] AFAIK, just smoke. Good question, but if they were tripped I’m assuming they’d make an alarm sound, not just the low battery ‘chirp’ sound every few minutes. ---
**Author:** ![Random](https://avatars.discourse-cdn.com/v4/letter/r/57b2e6/32.png) [@Random](https://boards.straightdope.com/u/Random)\ **Post date:** [December 23, 2007, 11:55pm UTC](https://boards.straightdope.com/t/why-are-my-smoke-detectors-beeping/431065/4 "2007-12-23T23:55:59Z")
How old are they? IIRC correctly, some detectors have a life expectancy after which they should be replaced, and some beep when this date is reached. ---
**Author:** ![Sunspace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sunspace/32/1250_2.png) [@Sunspace](https://boards.straightdope.com/u/Sunspace)\ **Post date:** [December 24, 2007, 12:03am UTC](https://boards.straightdope.com/t/why-are-my-smoke-detectors-beeping/431065/5 "2007-12-24T00:03:35Z")
[QUOTE=Random] How old are they? IIRC correctly, some detectors have a life expectancy after which they should be replaced, and some beep when this date is reached. [/QUOTE] I did not know this. ---
**Author:** ![Sub\_Judice](https://avatars.discourse-cdn.com/v4/letter/s/ba9def/32.png) [@Sub\_Judice](https://boards.straightdope.com/u/Sub_Judice)\ **Post date:** [December 24, 2007, 12:04am UTC](https://boards.straightdope.com/t/why-are-my-smoke-detectors-beeping/431065/6 "2007-12-24T00:04:36Z")
[QUOTE=Random] How old are they? IIRC correctly, some detectors have a life expectancy after which they should be replaced, and some beep when this date is reached. [/QUOTE] Hmm. House is 7 years old - I’d have thunk they’d be good for longer than that but I’ll check. Thanks ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [December 24, 2007, 12:11am UTC](https://boards.straightdope.com/t/why-are-my-smoke-detectors-beeping/431065/7 "2007-12-24T00:11:45Z")
Is your house on fire? (You didn’t mention this either to confirm or rule out). ---
**Author:** ![1010011010](https://avatars.discourse-cdn.com/v4/letter/1/ea666f/32.png) [@1010011010](https://boards.straightdope.com/u/1010011010)\ **Post date:** [December 24, 2007, 12:16am UTC](https://boards.straightdope.com/t/why-are-my-smoke-detectors-beeping/431065/8 "2007-12-24T00:16:45Z")
[QUOTE=Sub Judice] Any suggestion, pilgrims? [/QUOTE] If it’s the type that depend on beta or alpha radiation from an installed source being blocked by smoke to work, it could be that enough half-lives have passed that the source needs replacing. Probably not a user serviceable part in this here Era of Terror (pronounce it so it rhymes… like Dora the Explorer). Edit: Am-241 has a half-life over 400 years. ---
**Author:** ![danceswithcats](https://avatars.discourse-cdn.com/v4/letter/d/9e8a1a/32.png) [@danceswithcats](https://boards.straightdope.com/u/danceswithcats)\ **Post date:** [December 24, 2007, 12:52am UTC](https://boards.straightdope.com/t/why-are-my-smoke-detectors-beeping/431065/9 "2007-12-24T00:52:08Z")
A make and model of detector would be helpful. ---
**Author:** ![Sub\_Judice](https://avatars.discourse-cdn.com/v4/letter/s/ba9def/32.png) [@Sub\_Judice](https://boards.straightdope.com/u/Sub_Judice)\ **Post date:** [December 24, 2007, 12:53am UTC](https://boards.straightdope.com/t/why-are-my-smoke-detectors-beeping/431065/10 "2007-12-24T00:53:37Z")
[QUOTE=Mangetout] Is your house on fire? (You didn’t mention this either to confirm or rule out). [/QUOTE] Good call! I knew it would be something obvious ---
**Author:** ![LH75](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lh75/32/4438_2.png) [@LH75](https://boards.straightdope.com/u/LH75)\ **Post date:** [December 24, 2007, 3:44am UTC](https://boards.straightdope.com/t/why-are-my-smoke-detectors-beeping/431065/11 "2007-12-24T03:44:31Z")
I am lead technician for a small fire alarm company. Most often, the periodic “chirp” from a home type smoke detector is due to a bad battery, but sometimes, the detectors just go bad. They are rather inexpensive and easy to replace. ---
**Author:** ![Uncommon\_Sense](https://avatars.discourse-cdn.com/v4/letter/u/f9ae1b/32.png) [@Uncommon\_Sense](https://boards.straightdope.com/u/Uncommon_Sense)\ **Post date:** [December 24, 2007, 7:39am UTC](https://boards.straightdope.com/t/why-are-my-smoke-detectors-beeping/431065/12 "2007-12-24T07:39:57Z")
[QUOTE=longhair75] I am lead technician for a small fire alarm company. Most often, the periodic “chirp” from a home type smoke detector is due to a bad battery, but sometimes, the detectors just go bad. They are rather inexpensive and easy to replace. [/QUOTE] They’re putting lead in fire alarms now? When will the madness stop?! ---
**Author:** ![Nanoda](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Nanoda](https://boards.straightdope.com/u/Nanoda)\ **Post date:** [December 24, 2007, 10:08am UTC](https://boards.straightdope.com/t/why-are-my-smoke-detectors-beeping/431065/13 "2007-12-24T10:08:18Z")
If it keeps up after you extinguish the blaze, could you (after appropriate electrical precautions) disconnect one detector from the other? If one _is_ going bad, then I would think that procedure may help to identify which one that is. ---
**Author:** ![Philster](https://avatars.discourse-cdn.com/v4/letter/p/13edae/32.png) [@Philster](https://boards.straightdope.com/u/Philster)\ **Post date:** [December 24, 2007, 2:21pm UTC](https://boards.straightdope.com/t/why-are-my-smoke-detectors-beeping/431065/14 "2007-12-24T14:21:21Z")
You might want to power down the whole system, replace the batteries, and then start it up again. Kinda like rebooting. Worked for me. Also, the ‘chirping’ sounded like it was coming from detector 1 and 2, but just like a cricket’s chirp, it was deceiving me, and I had to circle back and replace another battery, as it wasn’t the detector I thought it was. ---
**Author:** ![Sub\_Judice](https://avatars.discourse-cdn.com/v4/letter/s/ba9def/32.png) [@Sub\_Judice](https://boards.straightdope.com/u/Sub_Judice)\ **Post date:** [December 24, 2007, 2:28pm UTC](https://boards.straightdope.com/t/why-are-my-smoke-detectors-beeping/431065/15 "2007-12-24T14:28:48Z")
[QUOTE=Philster] You might want to power down the whole system, replace the batteries, and then start it up again. Kinda like rebooting. [/QUOTE] That’s what I did. Will try again and note the make and model details ---
**Author:** ![fisha](https://avatars.discourse-cdn.com/v4/letter/f/da6949/32.png) [@fisha](https://boards.straightdope.com/u/fisha)\ **Post date:** [December 24, 2007, 2:33pm UTC](https://boards.straightdope.com/t/why-are-my-smoke-detectors-beeping/431065/16 "2007-12-24T14:33:39Z")
Welcome to the SDMB, **Sub Judice**. I’m sorry, but I just get this little grin thinking that the little chirping noise has been going on for a couple of days now. Surprised you haven’t shot the damn things yet. ---
**Author:** ![Sub\_Judice](https://avatars.discourse-cdn.com/v4/letter/s/ba9def/32.png) [@Sub\_Judice](https://boards.straightdope.com/u/Sub_Judice)\ **Post date:** [December 24, 2007, 2:55pm UTC](https://boards.straightdope.com/t/why-are-my-smoke-detectors-beeping/431065/17 "2007-12-24T14:55:40Z")
[QUOTE=fisha] I’m sorry, but I just get this little grin thinking that the little chirping noise has been going on for a couple of days now. Surprised you haven’t shot the damn things yet. [/QUOTE] It got bloody close! ☹ Another whoosh with the vacuum cleaner did the trick. ---
**Author:** ![BrandonR](https://avatars.discourse-cdn.com/v4/letter/b/779978/32.png) [@BrandonR](https://boards.straightdope.com/u/BrandonR)\ **Post date:** [December 24, 2007, 4:28pm UTC](https://boards.straightdope.com/t/why-are-my-smoke-detectors-beeping/431065/18 "2007-12-24T16:28:40Z")
Mine beeped semi-regularly all-day, everyday for about a year. The only thing I learned is how amazing my ears are at getting used to it and ignoring it. Now that I put two and two together, this detector was near my furnace (perhaps it’s a CO2/gas detector?) in comparison to my smoke alarm in the hall, so maybe I should get that checked out. At least I haven’t died yet! ---
**Author:** ![Fir\_na\_tine](https://avatars.discourse-cdn.com/v4/letter/f/a587f6/32.png) [@Fir\_na\_tine](https://boards.straightdope.com/u/Fir_na_tine)\ **Post date:** [December 24, 2007, 6:08pm UTC](https://boards.straightdope.com/t/why-are-my-smoke-detectors-beeping/431065/19 "2007-12-24T18:08:16Z")
[QUOTE=Sub Judice] It got bloody close! ☹ Another whoosh with the vacuum cleaner did the trick. [/QUOTE] Missed it by 4 hours! Yup, dust is the most common problem after batteries. Using the furniture brush will generally do the trick. ---
**Author:** ![Antinor01](https://avatars.discourse-cdn.com/v4/letter/a/ecae2f/32.png) [@Antinor01](https://boards.straightdope.com/u/Antinor01)\ **Post date:** [December 24, 2007, 8:19pm UTC](https://boards.straightdope.com/t/why-are-my-smoke-detectors-beeping/431065/20 "2007-12-24T20:19:59Z")
[QUOTE=Sub Judice] I have 2 mains-powered Smoke Detectors in my house that make a regular ‘chirp’ if the backup batteries are low. I’ve replaced the batteries in both with brand new Duracells, checked the main circuit breaker isn’t tripped, and I’ve vacuum-cleaned the sensors, as I’ve heard that can confuse the little buggers. Any suggestion, pilgrims? (Plan B may involve a large hammer, extreme violence and a misguided sense of my superiority over inanimate household fixtures) [/QUOTE] As Phoebe learned on [Friends](http://www.youtube.com/watch?v=19W45gXBrMM), that plan B idea doesn’t always pan out very well. (youtube link)