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.