Tuesday, December 27, 2016

When should you replace older ‘Smoke’ and ‘CO’ alarms?

This time of year the news media and fire departments are urging people to install fresh batteries every year in their Smoke and CO alarms and even if it appears functional to replace the entire alarm with a new one if your not sure of its age. Most models sold today have a manufacturer stated ten-year life span but some have only three! Read the packaging before buying. I just purchased three new CO alarms, made by Kidde. They had a nice feature where it will give warning chirps at the end of ten years use. The internal timer starts the minute you install the batteries in it.

For a reminder to replace the batteries in all my alarms I use Christmas, easy to remember for me. Also, I use a file folder label on each alarm that has the date of install and a reminder for the annual battery replacement.

This photo shows the Smoke and CO alarms I use in my van when using a catalytic heater.

Link below to comments and much more information from Consumer Reports article.

Q. I have two homes equipped with hard-wired smoke alarms, original equipment now about 17 years old. The alarms respond appropriately to the test buttons. But the instructions on a battery-operated alarm say it should be replaced in 10 years.

A. The life expectancy of smoke alarms is generally 10 years, after which point their sensors can begin to lose sensitivity. The test button only confirms that the battery, electronics and alert system are working; it doesn’t mean that the smoke sensor is working.
To test the sensor, use an aerosol can of smoke alarm test spray that simulates smoke. But even if the 17-year-old smoke alarms in your homes can still detect smoke, we recommend replacing them with new models.

Check our smoke alarm buying guide and Ratings to find the most effective models. 


  1. Mike, i would replace every three years, and not wait for ten, but that me. Batteries January 1st, and June 1st, You know that old battery is going to start chirping at O dark middle of the night.

    1. I would replace every six months if they didn't work or were questionable at the end of one year. But I have never had an issue with them going a year. I do volt check the old batteries. The "AA's" are at 1.4 volts and the 9v batteries are 8.1v and 8.4v plenty of power left to alert me. (I hope) :-)

  2. Mike,

    I never wait on the life expectancy to change out my alarms. They general are changed every couple of years. As for the batteries there changed twice a year, and tested monthly.

    1. That's a good plan Sandy. I've been using my method for many years and I'm comfortable with it. Mostly because I have two alarms in the house and one in the garage that can be heard in the house. So if one of the two in the house were to fail I'd have the second one as a back-up.


Your thoughts are welcome!