I’ve heard this advice since I was a child. However, I have not followed it as an adult since our smoke detectors are electric with battery backup. They chirp when the battery gets low. I figured this was a fool-proof method and never changed the batteries until they chirped. This week, we had a wake-up call that this does not work.
Our Smoke Detector Battery Wake Up Call
While we had power during the wind storm and it’s aftermath, we had a power outage earlier in the week. First the power went off for about a minute. Then, it came back on for 30 seconds. Finally, it went off for several hours. As soon as the power went out the second time, our smoke/carbon monoxide detectors started sounding with a carbon monoxide warning.
While I was 90% sure that it was a false alarm due to the timing, we still had the fire department perform a check. When I called (the non-emergency number), I was told that the fire department was already on the way to my neighborhood to respond to other alarms that started with the power outage.
The fire department verified that no carbon monoxide was present near our detectors. They advised that the alarm was probably due to a low battery even though they were not chirping. They recommended that we change the batteries. Sure enough once all 3 CO/Smoke detectors had new batteries the alarm stopped sounding. Upon replacing the batteries, we realized that they had not been changed since we installed new units in October 2014.
Of course our smoke alarm saga was not over. A couple of hours later when the power resumed, we started hearing the low battery chirp. Unfortunately, we started the day with only 6 9V batteries in a house with 3 combination smoke/CO detectors and 6 smoke detectors. After a quick run to the store, we managed to quiet the alarms.
And the saga still did not end, late Tuesday night the chirps started again. The original 6 9V batteries that we used for replacement had been in our basement for awhile. While they had an expiration date of 2018, clearly they were not providing enough charge for the detectors. Neither of us wanted to make a late night run for batteries, so we lived with it for the night. Wednesday, in the heart of the wind storm, I went out and bought new batteries. Finally, we got the chirping to stop.
We Were Not Alone
We were not alone in having smoke detectors sound with a power loss. My daughter and I both told other people about our experience with the carbon monoxide alarm sound. We both had people say that their smoke detectors alarmed when they lost power this week. Clearly this is not an isolated incident.
Suggestions for Smoke Detector Battery Replacement
Note, I am not a fire professional, and these are my opinions only. ;
Replace Smoke Detectors Every 10 Years
Smoke detectors have a finite life. They should be replaced every 10 years. I shared our experience with the smoke detectors not working after 11 years. We had filled the house with smoke after a cooking incident and our alarms did not work.
Battery Operated Detectors
Replace batteries in Battery Operated detectors twice a year when the clocks change. With the fluctuations in daylight saving time, another option is to pick 2 events and replace them then. For example, New Years and Father’s Day are roughly 6 months apart.
Now, there are battery operated detectors that come with a 10 year battery life. Since smoke detectors have a 10 year life, this is a great option for new units.
If you have a battery backup in your electric detector, my opinion is that they do not need to be replaced every 6 months. But, 2.5 years is too long to wait for replacement with alkaline batteries. I would suggest replacing the batteries yearly with alkaline batteries and after any extended outages.
We have switched to replacing our smoke detector battery with a long-lasting Lithium battery. They are designed to have a longer lifespan and are recommended for smoke detectors.