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Short answer: when you set your clocks back on Nov. 1, test every smoke and carbon monoxide alarm. If an alarm doesn’t have a sealed 10-year battery, put in fresh smoke alarm batteries. The U.S. Consumer Product Safety Commission says to change batteries at least once a year. It also says to toss any smoke alarm that is more than 10 years old and buy a new one.
Smoke alarm batteries: the checklist
The checklist below comes from the Consumer Product Safety Commission’s daylight saving time guidance. Test your smoke and CO alarms monthly. Swap the smoke alarm batteries at least once a year. Alarms with sealed 10-year batteries are the exception. And when an alarm itself passes 10 years old, replace the whole thing.
| Task | How often or when |
|---|---|
| Test smoke and CO alarms | Every month |
| Replace smoke alarm batteries | At least once a year (not needed for sealed 10-year battery alarms) |
| Replace the smoke alarm itself | When it is more than 10 years old |
Where alarms should go
So where do the alarms go? The CPSC’s answer is every level of the home, inside each bedroom, and just outside the sleeping areas. Carbon monoxide alarms belong on each level and near the bedrooms too. Here’s a common problem. A house has one old alarm in the hallway and nothing in the bedrooms. That’s the first gap to close. To check yours, count your levels, bedrooms, and sleeping areas. Then see whether each one has an alarm.
How to change smoke alarm batteries
Pick a day this weekend and do the whole house at once. That way you won’t have to remember which alarm got which battery. Press the test button on each alarm before and after the swap. A chirp every minute or so means a low battery. But silence doesn’t prove an alarm works, so test every one. Sealed 10-year units skip the yearly battery change, according to the CPSC. They still need a monthly test, and you replace the whole unit at the 10-year mark.
Check the manufacture date printed on the back of each alarm. If it is more than 10 years old, replace the whole unit, not just the batteries. Buy new alarms from a known retailer and read the instructions. Some models are designed to be wired in or interconnected.
Carbon monoxide matters more in winter
The CPSC notes that heating equipment and fuel-burning appliances get more use in colder months. That raises the importance of working alarms. According to the release, more than 400 people die each year from carbon monoxide poisoning, citing the CDC. Most of those deaths occur between November and February. If you heat with a furnace, fireplace, or space heater, check your CO alarms as carefully as your smoke alarms. Our guides to winter heating costs and LIHEAP heating help cover how to keep the house warm. The clock change is a good time to make sure it is also safe.
Make an escape plan, too
Alarms only help if you can get out. The CPSC advises giving every room two exits and keeping a clear path from each exit to the outside. Stay outside once you have escaped. It also says to keep bedroom doors closed during a fire, since that can slow the spread and buy time. The release cites a 2019 estimate of about 346,800 residential fires, about 2,490 deaths, and about 11,760 injuries. Fire deaths per household have fallen 66% since 1980. Our note on driving safety after daylight saving time ends covers the other clock-change risk.
Editor’s take
Tie the chore to something you already do. If you change your clocks twice a year, change your smoke alarm batteries then too. Test the alarms on the first of every month. It takes minutes, and a working alarm is the cheapest safety device in the house.
