How often should you test smoke alarms, and who can install them?

A smoke alarm is one of the cheapest and simplest safety devices in your home, but it only helps if it actually works. Dust, flat batteries and old age can all stop an alarm from doing its job. This guide covers how often to test and replace smoke alarms, which jobs you can do yourself, and when to book a licensed electrician.

How often should you test a smoke alarm?

Fire services across Australia give very similar advice. Fire and Rescue NSW's smoke alarm maintenance guide recommends this routine:

• Every month: press and hold the test button until the alarm beeps.
• Every six months: vacuum the dust off the alarm so smoke can reach the sensor.
• Every year: replace lead or alkaline batteries.
• Every 10 years: replace the whole smoke alarm, or earlier if the manufacturer says so.

The Victorian Building Authority gives the same monthly test advice and adds a useful tip: new units have an expiry date located under the battery. It also notes that a high-pitched single beep every 30 seconds usually means the battery needs replacing.

Why smoke alarms need replacing

Smoke alarms don't last forever. Fire and Rescue NSW explains that alarms can be affected by dust, insects, humidity and age, and that the sensitivity of all smoke alarms reduces over time. That's why it recommends replacing every alarm at least every 10 years, even if the test button still works.

The test button mainly checks the battery and the horn. It doesn't prove the sensor is still as sensitive as it was when new. If you've moved into an older home and can't find a date on the alarms, it's worth treating them as due for replacement.

Hardwired vs battery smoke alarms

There are two main types you'll find in Australian homes.

Hardwired (240-volt) alarms

These are connected to your home's electrical wiring, with a backup battery in case the power goes out. Building rules for newer homes generally call for hardwired alarms. In Victoria, for example, the Victorian Building Authority says homes built after 1 August 1997 must have smoke alarms connected to mains power with a backup battery.

10-year lithium battery alarms

These run on a sealed battery that lasts the life of the alarm. You don't change the battery; you replace the whole unit when it expires. Fire and Rescue NSW recommends hardwired, interconnected alarms wherever possible, and 10-year lithium battery alarms where hardwiring isn't possible.

What "interconnected" means

Interconnected alarms are linked, so when one detects smoke, they all go off. That matters most at night, when a fire in the kitchen or garage might not be heard from a bedroom at the other end of the house. Alarms can be linked by wiring or wirelessly.

Who can install smoke alarms?

This is where the type of alarm matters.

• Hardwired alarms: installing, replacing or rewiring a 240-volt smoke alarm is electrical work. It should be done by a licensed electrician. Consumer Affairs Victoria puts it simply: a hardwired smoke alarm must be installed by a qualified electrician, but anyone can change a smoke alarm battery.
• 10-year battery alarms: these generally don't involve any electrical work, so many homeowners fit them themselves. Follow the manufacturer's instructions and your state's placement rules.
• Testing: you don't need a tradie to press the test button. Queensland's government smoke alarm information notes that homeowners can test their own smoke alarms.

One important point: if your home already has hardwired alarms, don't swap them for battery-only units without checking your state's rules first. In Queensland, for example, WorkSafe Queensland says an existing hardwired 240V alarm must be replaced with a hardwired 240V photoelectric alarm.

You can find a local electrician through our electricians directory, or search by area such as electricians in Brisbane or electricians in Sydney.

Smoke alarm rules differ between states

Each state and territory has its own smoke alarm laws, covering things like how many alarms you need, where they go and what type is allowed. Rules for rental properties are usually stricter, and they change from time to time.

Queensland is a good example of why it pays to check. The Queensland Fire Department says all existing private homes, townhouses and units need interconnected photoelectric smoke alarms by 1 January 2027. If you own a home in Queensland and haven't upgraded yet, now is a good time to get quotes before the summer rush.

For the rules where you live, check your state fire service or building regulator. If you rent, your landlord or agent is generally responsible for installing and maintaining smoke alarms, so report any faulty alarm to them straight away.

Signs it's time to call an electrician

Book a licensed electrician if:

• a hardwired alarm keeps beeping after you've replaced the backup battery
• an alarm goes off for no reason, or keeps sounding after you've cleared any smoke or steam
• your alarms are more than 10 years old and are hardwired
• you want to add alarms to bedrooms or hallways, or interconnect your existing ones
• you're renovating and the work affects ceilings or wiring

While the electrician is there, it can be worth asking them to check your safety switches at the same time.

Getting a quote

Prices depend on how many alarms you need, whether they're hardwired or battery, how easy it is to reach the ceiling space, and where you live. Ask for two or three written quotes that list the alarm type and model, the number of alarms and whether they'll be interconnected. For hardwired work, ask the electrician what compliance paperwork you'll receive when the job is done, and keep it with your home records.

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Frequently asked questions

This guide is general information only, not legal or financial advice. Rules change, so check the official sources linked above for your state.