Smoke alarms

Why you need working smoke alarms

When you’re asleep, you lose your sense of smell. Don’t assume your smoke alarms are working. Press the button to check.

Buying a smoke alarm

Hard-wired or battery operated?

Wherever possible, we recommend hard-wired and interconnected smoke alarms are installed.

If your alarms cannot be hard-wired, we recommend long-life photoelectric smoke alarms that rely on long-life lithium batteries. Inbuilt long-life lithium batteries last as long as the smoke alarm so you don’t need to worry about replacing them every year – you simply replace the entire smoke alarm unit once every 10 years.

There are several specialised smoke alarms available for people who are deaf or hearing impaired. Find out more here.

Photoelectric vs. Ionisation?

Smoke alarms use either photoelectric or ionisation sensors to detect smoke. Some have both types of sensor (“dual” models).

Ionisation smoke alarms are typically more effective at detecting fast flaming fires, which burn and spread quickly. Photoelectric smoke alarms are typically more effective at detecting slow smouldering fires, which burn for hours before bursting into flame.

Unsure which type you have? Ionisation models require a tiny amount of radioactive material to make them work. You can identify one by the radiation symbol found on the plastic body.

Radioactive  symbol

The Residential Tenancy Act requires landlords to install and replace expired smoke alarms with long-life battery photoelectric smoke alarms. Further information can be found at:

How many do I need?

Smoke alarms cannot detect smoke through a closed door. Therefore, we recommend installing a smoke alarm in every bedroom, hallway and living area.

Please note: The New Zealand Building Code requires an approved smoke alarm to be fitted in every escape route (hallway) and within three metres of every sleeping space (bedroom) door.

Smoke alarm floor plan

Smoke alarms are available for purchase at most major supermarkets and hardware stores across New Zealand. Prices range from $6 - $75

Smoke alarm maintenance

It’s important to maintain smoke alarms regularly and check that they’re working.

Maintenance guide:


Once a month
Press the test button to sound the alarm

Tip - if you cannot reach the button easily, use a broom handle

Every 6 months
Vacuum or dust your smoke alarms to help reduce false alarms

Every year
Check the expiry date. This is usually located on the bottom or side of the alarm. If your smoke alarm does not have an expiry date on it, it is best to replace it.

Every 10 years
Replace all smoke alarms with new long-life photoelectric smoke alarms.

*If you have a replaceable battery smoke alarm, replace the battery every year. Please note: Your alarms will start to beep regularly if the battery is low.


Follow the testing and maintenance schedule provided by the installer.

Safe disposal of smoke alarms

When your smoke alarms fail, you can put them out in your normal rubbish disposal.

Further public advice is available at