mouseprint: fine print of advertising
Go to Homepage

Subscribe to free weekly newsletter

Mouse Print*
is a service of
Consumer World
Follow us both on Twitter:

Updated every Monday!   Subscribe to free weekly newsletter.

October 29, 2012

Carbon Monoxide Detectors: Guaranteed to Fail in 7 Years

Filed under: Business,Health,Retail — Edgar (aka MrConsumer) @ 6:17 am

Please Help Support Mouse Print*

Edgar Dworsky For 25 years, Consumer World, the creator of Mouse Print*, has served readers with the latest consumer news, money-saving tips, and independent investigations. It is your generosity (and not advertising nor corporate contributions) that keeps Mouse Print* and Consumer World available as free consumer resources. So MrConsumer turns to you and humbly asks for your support again this year. Your gift will be most appreciated.

Kidde alarmTo help prevent illness and death, some states require carbon monoxide alarms to be installed in various parts of your home.

Kidde is one of the large, recognized brands of smoke alarms and other fire prevention products. Certain of their carbon monoxide detectors, however, come with conflicting promises and warnings.

In the manual’s introduction for one of their basic carbon monoxide detectors, it reassures customers they have made a good choice:

“Thank you for making Kidde a part of your complete home safety program. With proper installation and use, your new Kidde CO alarm will provide you with years of dependable service.”

Buried on page 8, however, is some starting news:


Kidde 7 years

A similar disclosure appears in fine print on the box itself. On one hand, the company seems to take safety seriously and doesn’t want to give customers a false sense of reassurance that their detectors are working when they have really lost the ability to sense carbon monoxide. On the other hand, one would not normally expect to have to throw out a $25 to $70 product after only seven years.

What’s going on here? The answer is that carbon monoxide detectors do indeed have a limited life. Inside many detectors is an electro-chemical cell that reacts in the presence of carbon monoxide. It tends to be very accurate. But, over time, the chemical can degrade and its performance is diminished. Accordingly, a national safety standard for carbon monoxide detectors published by Underwriters Laboratories (UL) requires that manufacturers build in a warning system to alert consumers that the unit is no longer functioning properly.


8.1 The unit (including the sensor) shall have a specified lifetime of at least 3 years from the date of manufacture, or from the date the unit is placed into service.

38.1.6 The unit shall indicate end-of-life, based on the manufacturer’s specified lifetime, with an end-of-life signal (see 3.11). This signal shall be triggered either by an internal timer or by a self-diagnostic test(s).

3.11 END-OF-LIFE SIGNAL – An audible signal, differing from the alarm signal, intended to indicate that the device has reached the end of its useful life and should be replaced. … The end-of-life signal shall repeat once every 30 – 60 seconds ±10 percent. — UL 2034, Standard for Single and Multiple Station Carbon Monoxide Alarms.

So, no matter what brand of carbon monoxide detector you buy, the unit will automatically commit suicide at the end of its useful life.

Note: MrConsumer is a member of UL’s Consumer Advisory Council.

Share this story:

• • •


  1. I guess I better replace my detectors. It’s been way over seven years and no “end-of-life” signal either.

    Comment by Peter — October 29, 2012 @ 7:09 am
  2. When was that standard implemented? I have a Kidde plug-in CO detector, and it has been here for more than 7 years.

    Not a peep out of it, either!

    Edgar replies: Ken, I will ask UL when the rule about giving a warning “end of life” signal became effective.

    Edgar replies: The end of life signal became effective August 1, 2009, that is why older units don’t have it. UL suggests that you contact the manufacturer to find out when the unit may lose or already have lost its effectiveness.

    Comment by Ken — October 29, 2012 @ 10:13 am
  3. We have this brand after our state mandated owning one. Hadn’t noticed this small print. How irritating to have a built in failure so you have to buy new. Will have to do some better research when it does come time to replace. Thanks for the info.

    Comment by Lynda — October 29, 2012 @ 10:16 am
  4. I am glad to see that the CO detectors will tell you when they are not working. These detectors are life savers, and I would be upset if they didn’t give you a signal when they are not working. Buying a new CO detector is cheap life insurance; CO is deadly! Smoke/fire detectors for the most part also have a useful life (about 10 years) but I don’t know if they will alarm when they aren’t working. My son had several that were old and not working but gave no indication of their condition; he got his first indication when smoke from a kitchen mishap (nothing serious, fortunately) filled the house with smoke and no alarms sounded. He immediately replaced all of them.

    Comment by Richard J. Greer — October 29, 2012 @ 10:28 am
  5. Most people HAVE to have their phone updated once a year (or two) and in the process it usually costs them hundreds of dollars.

    Then again, I know people that think they would die without the “latest greatest”. I’m sure these people would not freak over having to update a true life saving device…..

    Comment by tom — October 29, 2012 @ 11:01 am
  6. To be honest this seems like a good thing. People are not aware that the detectors will be ineffective after a period of time and will neglect to replace them. By building in the signal the company is notifying the consumer that the product is no longer useful.

    Now, about the price. I guess that depends. I doubt the chemical cell costs that much per unit to manufacture, and the body is the detector is cheap plastic. I assume this article is really trying to point out that no matter how much you pay a CO detector is guaranteed to fail.

    Edgar replies: Wayne, the point of this story to bring to light fine print and an issue that consumers may not have caught or been aware of… that their carbon monoxide detectors have a limited life and will need periodic replacement. Would I prefer that I buy it once and that is it, sure. But knowing that they need replacement is valuable as well as annoying.

    Comment by Wayne R — October 29, 2012 @ 11:52 am
  7. 1) “8.1 The unit (including the sensor) shall have a specified lifetime of at least 3 years from the date of manufacture, or from the date the unit is placed into service.”

    This is written such that any detector in the store can be expired before you buy it because it could have been manufactured 3 years ago. does this mean it will beep when you bring it home and, um, plug it in?

    2) When CA mandated that we are all forced to have CO detectors in our house whether we are selling it or not, the law was promoted in a way that made it sound like a police state: they can come into your home and fine you if they do not find a CO detector. I hope this is not the case (although these days it’s hard to tell.) However, I suppose that if they find out you don’t have one, they might be able to get a search warrant…I’m still holding off until it’s time to sell the house.

    3) The few weeks before the law went into effect, the price of these skyrocketed without justification. They also kept promoting that these were only good for (typically) 7 years. I wondered what that meant…did they lose effectiveness after that point? How did I buy one that was good for more than 7 years. Now I understand why this limit was being promoted! THANKS!

    4) The law was written and promoted very deceptively of “it will save lives!” but when you check the numbers, you find that, in CA, (if I recall) about 50 families on average are “suspectible” to the conditions under which CO may be dangerous. I’m guessing that these are not the people with properly functioning equipment, which means that those who don’t have broken or dysfunctional stoves, etc are very unlikely to experience any problems ever, and if you have proper ventilation in your house, that makes it even less likely. Most likely, the only people who are likely to be affected are those poor people who (a) can’t afford to buy a CO detector (b) are not very well informed and probably don’t know about the law (c) will never have a CO detector until they try to sell their houses, which is unlikely since they tend to pass them along from family member to family member.
    Ultimately, this sounded to me like a corporate money-grab loaded with scare tactics, to get us to accept our gov’ts decision to make us buy a product to help protect us from something that is very unlikely to happen, and offer their corporate buddies a huge windfall of money.

    Sorry for the rant, but when I see the prices skyrocket after such a flimsy law, I can’t help but get angry! I’m surprised they haven’t mandated mouse-traps because some people may die from mouse feces. (And yes, I do believe in the effects of CO, but not the way it’s promoted.)

    Comment by RobS — October 29, 2012 @ 12:24 pm
  8. Correction to my #4 above, from CA state law SB 183, found here:

    Section 3, 13261. The Legislature finds and declares all of the following:
    (a) According to the American Medical Association, carbon monoxide
    is the leading cause of accidental poisoning deaths in the United States. The federal Centers for Disease Control and Prevention estimate that carbon monoxide kills approximately 500 people each year and injures another 20,000 people nationwide.

    (c) The State Air Resources Board estimates that every year carbon
    monoxide accounts for between 30 and 40 avoidable deaths, possibly
    thousands of avoidable illnesses, and between 175 and 700 avoidable
    emergency room and hospital visits.

    So given that CA has abut 10% of the US population, that would be about 50 people that may die from CO poisoning. And taken nationwide, although this is certainly an issue, we’re talking about 500/350,000,000 = .0000014% of the population die from this. Is that worth mandating CO detectors? I leave that up to the reader, knowing that there are thousands of risks in every day life, and if we created “detectors” for every one of those with a higher risk, we’d probably all pay many hundreds of thousands of dollars every few years to protect ourselves. Should we have eColi detectors? EMT emission tests? Japanese nuclear power plant radiation detectors? solar radiation detectors? ground water impurities detectors for park water fountains? high-frequency noise detectors outside of the human hearing range that could harm us? medicine impurities detectors? etc.

    Comment by RobS — October 29, 2012 @ 12:51 pm
  9. Thumbs up for Richard, tom and Wayne for rational thought. Edgar, there is a similar notice/warning on many products – fire extinguishers being just one example. I’m sure by now mine have exceeded their lifespan for reliability, but I haven’t changed or recharged them. That’s my fault. Perhaps if they would beep at me I’d be more likely to give them the attention they need.

    Comment by Toddy541 — October 29, 2012 @ 1:48 pm
  10. A bit deceptive but truthful in the way it is written. The description says “…will provide you with years of dependable service.” Nowhere does it say “lifetime” of service, so any dependable service from two years and beyond is okay with me just as long as it doesn’t chirp too soon. Based on the above comments, it looks like these detectors are doing what it’s suppose to be doing within a reasonable period of time.

    Comment by Frankie — October 29, 2012 @ 2:14 pm
  11. That is so funny to read this now. The CO detector in my bedroom stopped working, but without any beeps or anything. My dad bought a new one, and when he was reading the instructions found the label that said it would stop working in 7 years. That’s exactly how long we had the one that stopped working.

    Comment by Jared G — October 29, 2012 @ 4:48 pm
  12. “This signal shall be triggered either by an internal timer or by a self-diagnostic test(s).”

    Does the aforementioned test actually measure the effectiveness of the CO sensor? If so, this would be preferable to a simple timer.

    As an aside, the comment about “Most people HAVE to have their phone updated once a year (or two) . . . ” is nonsense.

    Comment by Jon — October 29, 2012 @ 4:59 pm
  13. my detector started chirping in the middle of the night, after regaining my wits, i wondered why it chirped since i had a voice model..yep, time to replace. it was four years old. a side note to Mr. Consumer, my new unit also stated not to use the the garage. i have a unit in every room including the garage…ok,not the bathrooms..all my units have a test button that i push once a month during daylight hours. i hope i never get to test them for real.

    Comment by tom gauvin — October 29, 2012 @ 9:35 pm
  14. Funny how people are perfectly willing to spend a few hundred dollars every year or two on a new cell phone, but get really upset at spending a few hundred every seven years on something that could actually save their lives.

    Comment by Jack — October 29, 2012 @ 10:52 pm
  15. I wonder how many people install CO detectors in houses heated with heat pumps? If you heat electrically and don’t have a fireplace, there is no reason to have a CO detector.

    Comment by John — October 30, 2012 @ 8:27 am
  16. Edgar, What about the statement below (From RobS’ first post)?

    “1) “8.1 The unit (including the sensor) shall have a specified lifetime of at least 3 years from the date of manufacture, or from the date the unit is placed into service.”

    This is written such that any detector in the store can be expired before you buy it because it could have been manufactured 3 years ago. does this mean it will beep when you bring it home and, um, plug it in?”

    Edgar replies: I don’t know, Gert. You could be right.

    Comment by Gert — October 30, 2012 @ 1:41 pm
  17. Not only do carbon monoxide detectors expire, but so do smoke detectors. Depending on the type, they need to be replaced every 7-10 years.

    Comment by Laura — October 31, 2012 @ 9:40 am
  18. Had a chirping smoke alarm that I’d taken down 2 years ago and never bothered to replace (a second good one is located nearby). Since it began chirping while still plugged into 120 VAC power, I figured it had simply died of old age. Had to remove the battery to stop the chirping that was driving me insane but never realized that chirping had been designed into the alarm to warn of an unsafe condition. After reading Laura’s “so do smoke detectors”, I looked over the alarm closely (still had it on the recycle shelve) and found the fine print molded on the inside surface of the battery compartment door that said chirping meant the battery needed replacement. The chirping stopped with a new battery and it’s back up on the wall, plugged in and tested. Thank you, Mouse Print and Laura!

    Comment by anonymous — October 31, 2012 @ 8:21 pm

Comments RSS

Sorry, the comment form is closed at this time.

Powered by: WordPressPrivacy Policy
Mouse Print exposes the strings and catches buried in the fine print of advertising.
Copyright © 2006-2020. All rights reserved. Advertisements are copyrighted by their respective owners.