Fire safety is something many of us take for granted—until it’s too late. We install smoke detectors in our homes and assume they’ll always work when needed. But like any household device, smoke detectors don’t last forever. Knowing when and how to replace them is crucial to ensuring your family’s safety.

How Long Do Smoke Detectors Last?

Many people assume that as long as their smoke detector beeps when tested, it’s still effective. However, most smoke detectors have a lifespan of around 10 years. Over time, dust, debris, and environmental factors can impact their sensors, making them less reliable in detecting smoke.

If your smoke detector is over a decade old, it’s time to replace it—even if it seems to be functioning normally. Manufacturers often print the manufacture or expiry date on the back of the unit, so it’s a good idea to check periodically.

Signs Your Smoke Detector Needs Replacing

Even before the 10-year mark, certain signs indicate your smoke detector may no longer be effective:

• Frequent false alarms – If your alarm is going off without smoke present, the sensors may be compromised.

• No response during testing – If pressing the test button doesn’t produce a loud alarm, the detector may be faulty.

• Chirping sounds – A continuous beeping noise could indicate a low battery, but if replacing the battery doesn’t help, the unit itself may need replacing.

• Physical damage – Smoke detectors exposed to excessive dust, moisture, or physical damage may not work properly.

How to Replace a Smoke Detector

Replacing a smoke detector is simple and can be done without professional help. Here’s how:

1. Turn off power (if wired in) – If you have a hardwired smoke alarm, switch off the power at the circuit breaker before removing it.

2. Remove the old unit – Twist the detector counterclockwise to detach it from the mounting bracket.

3. Disconnect the wiring (if applicable) – If the alarm is hardwired, carefully unplug the connector.

4. Install the new detector – Align the new detector with the bracket and twist it into place. If it's a hardwired model, connect the wiring before securing it.

5. Test the alarm – Press the test button to ensure it functions correctly.

The Best Smoke Detectors for NZ Homes

Not all smoke detectors are created equal. In New Zealand, it’s recommended to install photoelectric smoke detectors, as they are more effective at detecting smouldering fires and reducing false alarms. Some modern models come with long-life lithium batteries, eliminating the need for frequent battery changes.

For optimal safety, interconnected alarms are recommended, so if one smoke detector goes off, all alarms in the home will sound, providing better coverage.

Maintenance Tips to Keep Your Smoke Detector Working

Simply installing a smoke detector isn’t enough—you need to maintain it properly to ensure it functions when you need it most. Here are some maintenance tips:

• Test your alarm monthly – Press the test button to ensure it sounds correctly.

• Clean the detector regularly – Dust and debris can clog the sensors, so vacuuming around the unit every few months can help maintain sensitivity.

• Replace batteries yearly (if applicable) – If your smoke detector uses removable batteries, change them at least once a year.

• Replace the unit after 10 years – Even if it seems functional, outdated alarms may not provide reliable protection.

Final Thoughts

A smoke detector is one of the most vital safety devices in your home, but only if it’s working properly. If yours is more than a decade old or showing signs of malfunction, it’s time to replace it. Regular maintenance and timely replacements ensure your household remains protected from potential fire hazards. Take a moment today to check your smoke detectors—you never know when they might save a life.