04/08/2026
Smoke alarms. They’re in our homes, they criticise our cooking, and most importantly, they save lives. But have you ever wondered how they actually work?
Most modern smoke alarms - and ones we recommend, use a photoelectric sensor. Inside the alarm is a small beam of light and a sensor that sits out of the light’s path.
When the air is clear, the light never reaches the sensor. But when smoke enters the alarm, the smoke particles fracture the light, causing some of it to hit the sensor. When there is enough interference from smoke, and more light reaches the sensor, that then triggers the alarm to sound.
However, this is also how false alarms can happen. If enough dust particles build up inside the sensing chamber, that can interfere with the light beam in the same way smoke does and trigger the alarm.
That's why keeping your smoke alarms clean is so important.
✅ Vacuum your smoke alarms regularly using a soft brush attachment.
✅ Keep them free from dust, cobwebs, and insects.
✅ Test them monthly to make sure they're working.
✅ Replace the entire alarm when it reaches the end of its service life (usually 10 years).
A clean smoke alarm is a reliable smoke alarm. By taking a few minutes to maintain yours, you'll reduce nuisance alarms and help ensure it works when you need it most.
After all, the smoke alarm that goes off during burnt toast today could be the one that saves your life tomorrow.
Take a moment today to check your smoke alarms. Are they clean, tested, and ready to protect your whānau?
https://www.fireandemergency.nz/home-fire-safety/smoke-alarms/
