Types of Smoke Alarms: Ionisation vs Photoelectric

There are two main types of smoke alarm technology: ionisation and photoelectric. Queensland law now requires all domestic smoke alarms to be photoelectric only, complying with AS 3786:2014. Ionisation alarms — once the most common type sold at hardware stores — are no longer permitted in Queensland homes under the Fire and Emergency Services (Domestic Smoke Alarms) Amendment Act 2016.

If your home still has ionisation alarms, they need to go. This guide explains why that decision was made, how each technology actually works, and what it means for your Toowoomba home.

The science behind this decision is straightforward. Research shows that smouldering fires account for the majority of residential fire deaths — precisely because they develop slowly overnight while occupants are asleep, filling rooms with toxic smoke before flames take hold. Ionisation alarms can take up to 30–60 minutes longer to detect this type of fire compared to photoelectric units.

In older Toowoomba homes — particularly the timber Queenslanders in East Toowoomba, Rangeville, and Newtown — a slow-burning fire starting in wall cavities or roof spaces is a genuine risk. All-timber construction means a smouldering fire can spread significantly before breaking into open flame. An ionisation alarm in that scenario could wake you far too late.

Queensland Fire Department data supports the move. Research cited during the legislative review indicated that the risk of dying in a house fire is reduced by half with working smoke alarms, and that more than one-third of residential fire deaths occur in homes without functioning alarms. Specifying the most effective technology was the logical next step.

The legislation also addressed a behavioural problem: ionisation alarms' tendency to false-alarm during cooking led many homeowners to remove batteries or disable alarms entirely. Photoelectric alarms have a lower nuisance alarm rate, which means they're more likely to still be operational when you actually need them.

"My old alarm still works, so it must be fine."

Working and compliant are two different things. If your alarm is an ionisation type, it doesn't matter that it still chirps when you press the test button — it must be replaced. Check the label on the back of your alarm: it should say "Photoelectric" and carry the AS 3786:2014 mark. If it says ionisation or dual-sensor, it's non-compliant.

"I bought this alarm from Bunnings, so it must be legal."

Bunnings and other retailers stock both compliant and non-compliant alarms. The fact that an alarm is available for sale in Queensland does not mean it meets the state's residential compliance requirements. Always check the packaging for the words "photoelectric" and the AS 3786:2014 standard before purchasing.

"Wireless interconnected alarms aren't as reliable as hardwired ones."

Modern wireless interconnection technology using 433MHz or 868MHz radio frequencies is highly reliable. Queensland law explicitly permits wireless interconnection as an alternative to hardwired 240V systems, provided all alarms in the dwelling communicate with each other. For heritage Queenslanders where running new cables through walls is expensive or structurally difficult, wireless interconnection is often the most practical and cost-effective solution.

"Smoke alarms in apartments trigger alarms in other units."

Interconnection under QLD legislation is required only within the same dwelling. Alarms in your unit activate all alarms within your unit — not your neighbours'. Apartment buildings with shared fire systems operate under different commercial building regulations, not the domestic smoke alarm legislation.

Identifying your alarm type takes about 30 seconds if you know what to look for — but the consequences of getting it wrong range from a non-compliant property to a smoke alarm that doesn't wake you when it matters most.

We work across Toowoomba and the Darling Downs, installing compliant photoelectric interconnected systems in everything from modern Highfields builds to 100-year-old Queenslanders in East Toowoomba. If you're unsure whether your current alarms meet Queensland's requirements, we'll check them and give you a straight answer.

Call 0494 652 176 to book an inspection or get a quote for full compliance installation. No jargon, no pressure — just honest advice from a licensed Toowoomba electrician.