A smoke alarm is a small thing to look after. Most of the time it sits on the ceiling and you forget about it. Yet it is often the first warning you get that something is burning. That early warning gives you time to get everyone out.
This post covers the types of alarms, where they go and how to test and clean them. It also explains when to replace them. Rules for homes are set by each state and territory, so the details differ around Australia. They also change over time, so check the current rules with your local fire service.
Why smoke alarms matter at home
Fire can spread quickly through a house, and smoke can fill rooms well before flames reach them. The South Australian Metropolitan Fire Service says correctly located working smoke alarms give early warning of fire. That warning matters most at night, when people are asleep. An alarm that works is one of the simplest safety steps in any home.
Alarms work best as part of a wider plan. Many households keep a fire blanket in the kitchen for small pan fires. If you have one, it helps to know how to look after and use a fire blanket as well. A clear escape plan that everyone in the family knows is just as useful.
Photoelectric and ionisation alarms
Domestic smoke alarms are either photoelectric or ionisation types. The SA fire service notes that ionisation alarms contain a minute particle of radioactive material. Both types are still found in Australian homes. However, fire services and several state laws now favour photoelectric alarms.
The SA Metropolitan Fire Service recommends 240 volt photoelectric alarms for the best protection, and says they should be interconnected. In Queensland, alarms must be photoelectric and must not contain an ionisation sensor. The Northern Territory also defines an approved alarm as a photoelectric type. It must be either hardwired or a sealed lithium battery unit with a ten year life.
The Australian Standard
Only smoke alarms that comply with Australian Standard 3786 can be installed in homes in Australia. In Queensland, alarms must comply with AS 3786:2014. The Queensland Fire Department says this is marked on the body of the alarm. Check the label before you buy a replacement.
Hardwired or battery powered
Alarms are powered in one of two ways. Hardwired alarms run off the home’s 240 volt supply and have a battery as backup. Battery alarms use either a replaceable battery or a long life battery that lasts ten years. Both can do the job if they are the right type and kept in working order.
Hardwired alarms must be put in by a licensed electrician. Battery alarms can usually be fitted by the householder, following the maker’s instructions. In Queensland, owners can choose sealed photoelectric alarms with batteries that last ten years and install them themselves. Read the box and the instructions before you start.
Interconnected alarms
Interconnected alarms are linked, so when one detects smoke, they all sound together. This means a fire in the living room can wake someone asleep at the other end of the house. In SA, interconnection is a legal requirement in new homes built since 2014. The NT notes a similar rule for new or renovated homes under the National Construction Code since 1 May 2014, where there is more than one alarm.
Queensland has set a firm deadline. Its rules require existing private homes, townhouses and units to have interconnected photoelectric smoke alarms by 1 January 2027. Rental homes and homes being sold already have to meet these rules. You can read the details on the Queensland Fire Department smoke alarm page.
If you are planning a renovation, ask about alarms early. Building work can trigger extra requirements in some states. For example, if you hire a bathroom remodelling team, ask whether the work affects your alarm wiring. It is easier to sort out while walls and ceilings are already open.
Where to put smoke alarms
Placement rules vary between states, but they follow the same idea. Alarms go where they will wake sleeping people and where smoke will travel. In Queensland, alarms are required on each storey and in each bedroom, or where you sleep. They also go in hallways that connect bedrooms to the rest of the home.
The NT gives some helpful mounting guidance. Fit alarms on or near the ceiling, and keep them out of the corner where a wall meets the ceiling. If a ceiling mount is not practical, the alarm can go on a wall between 300mm and 500mm below the ceiling. On a cathedral ceiling, keep the alarm between 500mm and 1500mm from the highest point.
Homes with more than one level need extra care. The NT advises an additional alarm in the stairway between each level. Some homes also have long hallways or rooms that are closed off at night. Add alarms there if people sleep with the door shut.
Testing and cleaning
An alarm only helps if it works. Dust and flat batteries can stop it doing its job. The SA fire service suggests a simple routine for each alarm:
- Test it once a month by pressing and holding the test button until it sounds.
- Clean it every six months using a vacuum cleaner with a soft brush attachment.
- Change a replaceable battery once a year, or sooner if it gives a low battery beep.
For hardwired alarms, the SA advice is to turn off the power at the main switch or circuit breaker before testing the backup battery. With interconnected alarms, check that all of them sound at the same time. Test again after cleaning. More detail is on the SA Metropolitan Fire Service smoke alarm fact sheet.
Never take out the battery or disable an alarm to stop a nuisance alarm. The Queensland Fire Department warns this can become dangerous and put you and your family at risk. If an alarm keeps going off while you cook, the position may be the problem. Ask an electrician whether it can be moved.
When to replace smoke alarms
Smoke alarms do not last forever. The SA fire service says all domestic smoke alarms should be replaced after ten years, whatever their power source. Older alarms may malfunction or stop working entirely. Check the label on each alarm so you know how old it is.
Write the replacement date somewhere you will see it. The Queensland Fire Department suggests recording it or setting a reminder. This is also a good job to do for older relatives. If you are helping a parent with retirement financial planning, add a check of the alarms in their home to the list.
Disposing of old alarms
Old alarms need different handling depending on type. The SA fire service says old photoelectric alarms can go out with normal household rubbish. Ionisation alarms should go to a dedicated recycling facility. Your local council can tell you where to take them.
Renters, landlords and people selling
Responsibility for alarms often changes when a home is rented. In SA rental homes, the owner is responsible for installing and maintaining smoke alarms. In the NT, owners and tenants must each test the alarms at least once every 12 months. Tenants there must also tell the owner or agent if an alarm does not work.
In Queensland, landlords must test and clean each alarm within 30 days before a tenancy starts. Renters there must test and clean each alarm at least once every 12 months. Sellers in Queensland must also upgrade alarms before a sale goes through. Your state fire service or tenancy body can explain the rules where you live.
Spending on the home is often focused on things you can see. New paving or plants from landscaping services can lift a property. A set of working, correctly placed alarms costs far less and protects the people inside. It is worth doing before the bigger projects.
Frequently asked questions
How often should I test my smoke alarms?
The SA Metropolitan Fire Service suggests testing each alarm once a month. Press and hold the test button until it sounds. Some states also set minimum testing rules for owners and tenants.
How long does a smoke alarm last?
The SA fire service says domestic smoke alarms should be replaced after ten years. This applies whatever the power source. Check the date printed on the alarm.
Can I install a smoke alarm myself?
Battery alarms can usually be fitted by the householder using the maker’s instructions. Hardwired alarms must be installed by a licensed electrician. Check your state rules before you buy.
Do people who are deaf or hard of hearing have options?
Yes, there are alarm systems that use strobe lights and vibrating elements. The SA fire service mentions these on its fact sheet. In Queensland, a subsidy scheme helps with the cost of specialty alarms.
This post is general information only. Smoke alarm laws differ between states and territories and can change. Check the current rules with your local fire service before you buy or install alarms.