When should you replace a smoke detector?

Roots plans for year 10, measured from installation. That is a planning horizon, not an expiry date: budget for the replacement then, and keep using it while it works.

By Roots Team · Jul 10, 2026 · Updated Aug 17, 2026

How long does a smoke detector last?

Q: How long does a smoke detector last?

Typically 10 years. Roots plans a replacement at year 10.

How long a smoke detector lasts

Published service life: 10 years. Roots plans for: year 10.

Service life is a planning horizon, not an expiry date. It tells you when to start budgeting, get a second quote, and stop paying for repairs on something near the end — not the day it stops working.

What changes this

Both spine charts print "<10" and NAHB names the code directly. Note the unit is dated from MANUFACTURE, not installation, and the date is stamped on the back — a detector bought two years after it was made is already two years into its life. Combination CO units are shorter still, commonly 5–7 years.

Sources

NFPA 72, the National Fire Alarm and Signaling Code (the 10-year replacement requirement, as cited in NAHB's comment column), cross-checked against InterNACHI's Standard Estimated Life Expectancy Chart for Homes (Smoke/Heat Detectors, printed as "less than 10").

Service-life figures are typical estimates drawn from published industry references. Where a second reference covers the component, the figure is cross-checked against it and any disagreement is set out above; where only one reference covers it, that is stated. Actual life varies with installation, water quality, climate, and maintenance, and these figures shouldn't be relied on for insurance, lending, or warranty decisions.

Maintenance is what decides where in the range you land

The published range is wide for a reason: two identical units, installed the same day, routinely fail years apart. What separates them is upkeep.

For a smoke detector, the tasks that matter most:

Test smoke and CO detectors — A dead detector protects no one. The test button takes ten seconds.
Replace smoke detector batteries — Annual swaps prevent dead detectors (sealed 10-year units can skip this).
Replace smoke and CO detector units — Sensors wear out: smoke detectors last ~10 years, CO detectors ~5-7. Check the date on the back.

Roots tracks the age of every component in your home alongside the upkeep that extends it, so the replacement is a planned expense instead of an emergency.

Free tool Know what's due before it fails Knowing how long a component lasts only helps if you're maintaining it. Build a free maintenance checklist tuned to your home. It takes about 30 seconds and there is no signup.

Build it →

Frequently asked questions

How long does a smoke detector last?: Typically 10 years. Roots plans a replacement at year 10.
When should you replace a smoke detector?: Roots plans for year 10, measured from installation. That is a planning horizon, not an expiry date: budget for the replacement then, and keep using it while it works.
What shortens the life of a smoke detector?: Both spine charts print “<10” and NAHB names the code directly. Note the unit is dated from MANUFACTURE, not installation, and the date is stamped on the back — a detector bought two years after it was made is already two years into its life. Combination CO units are shorter still, commonly 5–7 years.

Never think about this schedule again.

Roots builds your home's maintenance plan automatically: every task above, timed to your home, with reminders and a Home Health Score that tracks your progress.

Get Roots free →