How Long Do Smoke Alarms Last? 10 Years, Even Hardwired
Smoke alarms last 10 years from the manufacture date printed on the back, not the install date. That goes for battery, 10-year sealed and hardwired alarms. Carbon monoxide and combo alarms last 5–10 years depending on the brand. Past that date, replace the whole unit, even if the test button still works.
Here's the fact most homeowners have never been told: smoke alarms expire. Every smoke alarm and smoke detector — hardwired or battery, cheap or premium — has a maximum service life of 10 years from its manufacture date. After that, it must be replaced. Not because the battery dies, but because the sensor itself wears out.
Why Do Smoke Detectors Expire After 10 Years?
Every smoke alarm, photoelectric or ionization, senses smoke in a small chamber. Over a decade, dust accumulation, humidity cycles, insect debris, and chemical aging of the sensor components all degrade that chamber. That's why every major manufacturer — and Canada's smoke alarm maintenance standard, CAN/ULC-S552 — calls for replacement 10 years after the manufacture date, regardless of how the alarm seems to perform.
The test button won't save you. Pressing "test" confirms the horn and circuit work — it does not test whether the sensing chamber can still detect smoke. An expired alarm can pass its button test every week and still fail in a real fire.
How Do I Know How Old My Smoke Detector Is?
- Twist the unit off its bracket (hardwired units stay connected by a plug — just let it hang).
- Look at the back for a printed date stamp or sticker: "Manufacture date" or "Replace by."
- Count from the manufacture date, not the day it was installed. A unit made in 2016 and installed in 2019 expired in 2026.
- No date visible? Replace it. Alarms without date stamps predate modern labelling standards and are almost certainly past service life.
Smoke, Fire and CO Alarm Lifespan Chart
| Device | Lifespan | Battery |
|---|---|---|
| Smoke alarm (9V or AA battery) | 10 years | Replace yearly |
| 10-year sealed battery smoke alarm | 10 years | Never — replace whole unit |
| Hardwired smoke alarm | 10 years | Backup battery every 1–2 years |
| Combination smoke/CO alarm | 5–10 years (check the label) | Model-dependent |
| Standalone CO detector | 5–10 years (check the label) | Model-dependent |
How Do I Know If My Smoke Detector Is Outdated?
- Manufacture date more than 10 years ago (or missing entirely)
- Yellowed or discoloured plastic housing
- Frequent false alarms from cooking or steam that never used to happen
- Chirping that continues after a fresh battery
- It's an older ionization model that goes off every time someone cooks or showers — photoelectric is preferred in BC, and required in houses with a secondary suite
How Long Do Hardwired Smoke Alarms Last?
Ten years, the same as battery alarms. Being wired into the house only powers the alarm; the sensor inside still wears out on the same clock. The backup battery is a separate job: swap it every 1–2 years, or never on sealed 10-year models.
Replacing a hardwired alarm means matching the plug and brand already in your home so the interconnect keeps working, then testing every alarm on it. That's most of what I do on a smoke alarm replacement visit.
How Long Do Fire Alarms Last in a House?
In a home, the "fire alarm" is the smoke alarm on your ceiling, so the same 10-year rule applies. Count 10 years from the date on the back.
Will an Expired Smoke Alarm Keep Beeping?
Often, yes. Many sealed 10-year alarms give an end-of-life chirp that comes back no matter how many times you press the button. A new battery won't stop it, because there's nothing left to fix. The only cure is replacing the alarm. If yours is chirping and you're not sure why, see why is my smoke alarm beeping.
What BC Law Requires When You Replace
Smoke detector replacement is the right time to bring a home up to current practice: photoelectric units (required in houses with a secondary suite), an alarm on every storey and outside the sleeping area — plus one in each bedroom in homes built or renovated to current code — and interconnection where the code calls for it. If you're selling or renting out a property, expect home inspectors to check the date stamps. Full details in our BC smoke alarm laws guide, and landlords should see the landlord compliance checklist.
Not sure how old your alarms are?
Richard checks the date on every alarm in your home, replaces what's expired with premium 10-year Kidde or BRK / First Alert units matched to your system, and leaves you a written record of every alarm. $99.99 flat service fee — same-day or next-day across Vancouver and the Lower Mainland.
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Frequently Asked Questions
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We install and replace smoke and CO alarms across the Lower Mainland, including Vancouver, Burnaby, Richmond, Surrey, Coquitlam, New Westminster, North Vancouver, Maple Ridge, Langley. See current prices.