How Long Do Smoke Alarms Last? The 10-Year Rule Explained
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 Smoke Alarms Expire After 10 Years
Modern residential alarms in BC are photoelectric: a small chamber uses a light beam to detect smoke particles. Over a decade, dust accumulation, humidity cycles, insect debris, and chemical aging of the sensor components all degrade that chamber. Research by manufacturers and fire authorities shows detection reliability drops significantly past the 10-year mark — which is why the BC Fire Code requires replacement at or before 10 years, regardless of how the alarm seems to perform.
How to Check Your Smoke Alarm's Age
- 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.
Alarm Lifespans at a Glance
| 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 | 7–10 years (check label) | Model-dependent |
| Standalone CO detector | 7–10 years | Model-dependent |
Signs Your Alarm Is Past Its Prime
- 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 ionization model — never compliant with BC's photoelectric requirement
What BC Law Requires When You Replace
Replacement units must be photoelectric, installed on every storey and outside each sleeping area, and interconnected in new construction and most renovations. If you're selling, renting out, or refinancing a property, expect to show your alarms are within their service life — many insurers and buyers' inspectors check 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 sealed Kidde units, and leaves you a signed compliance certificate. $99.99 flat service fee — same-day across Vancouver and the Lower Mainland.
Book a replacement visitFrequently Asked Questions
How long do smoke alarms last?
10 years from the manufacture date printed on the back of the unit — not from the installation date. After 10 years the sensing chamber degrades and the alarm must be replaced under BC Fire Code, even if it still beeps during a test.
How do I check how old my smoke alarm is?
Twist the alarm off its mounting bracket and look for a date stamp or sticker on the back. If there's no visible date, the alarm almost certainly predates modern labelling requirements and should be replaced.
Do 10-year sealed battery alarms really last 10 years?
Yes — sealed lithium battery alarms like the Kidde 10-year series are designed so the battery and the sensor reach end of life together. You never change the battery; you replace the whole unit at the 10-year mark.
My smoke alarm passes the test button — does it still need replacing?
The test button only confirms the horn and circuitry work. It cannot test whether the sensing chamber still detects smoke reliably. An expired alarm can pass the button test and still fail in a real fire.
How much does smoke alarm replacement cost in Vancouver?
A flat $99.99 service fee plus units — 10-year sealed combination smoke/CO detectors from $79.99. Every replacement includes testing, disposal of old units, and a signed compliance certificate.