Short answer: A home alarm system uses sensors (motion detectors and door or window reed switches), a control panel with a keypad or app, and a siren, with optional monitoring. You can choose wired or wireless sensors and self-monitoring through an app or back-to-base monitoring by a security company. In NSW, anyone paid to install or service alarms needs a Class 2C security licence, so ask to see it.
Alarm systems have changed a lot. The old beige keypad by the front door is now an app on your phone, with sensors that talk wirelessly and cameras that show you what triggered the alarm. Here’s how to choose a system that suits your home and your routine.
The parts of an alarm system
| Part | What it does |
|---|---|
| Control panel | The brain. It receives sensor signals and decides when to sound the alarm |
| Keypad or app | Arms and disarms the system |
| Motion detectors (PIRs) | Detect movement in rooms and hallways |
| Reed switches | Detect a door or window opening |
| Siren and strobe | Make noise and flash outside to deter and alert |
| Communicator | Sends alerts to your phone or a monitoring centre over 4G or the internet |
| Backup battery | Keeps the system running in a power cut |
Wired or wireless?
Wired sensors
Each sensor is cabled back to the panel.
- Pros: no sensor batteries, very reliable, good for renovations and new builds
- Cons: cabling through ceilings and walls, which is harder in terraces with no roof access
Wireless sensors
- Pros: fast installation, minimal disruption, easy to add sensors later
- Cons: sensor batteries need replacing; very thick double brick walls can affect range
Many homes use a hybrid: wired where cables are easy to run, wireless elsewhere.
Monitoring: who responds?
Self-monitoring
Alerts go to your phone. You decide what to do, such as checking a camera, calling a neighbour or calling police. No monthly fee, but you need to be reachable.
Back-to-base monitoring
Alerts go to a monitoring centre, which follows an agreed response plan, such as calling you or sending a patrol. There’s an ongoing fee, and the provider needs the right security licence.
Smart home integration
Some alarms connect to smart home hubs, so arming the alarm can turn lights off and lock doors. See our smart home wiring guide.
Avoiding false alarms
False alarms annoy neighbours and can cost money if a patrol attends. Common causes include:
- pets triggering motion detectors (use pet-friendly sensors and placement)
- curtains moving near heater vents
- spiders and insects on sensors
- doors and windows not fully closed when arming
A careful zone plan at installation prevents most of these.
The licence installers need
In NSW, installing, maintaining and servicing security equipment is a licensed security activity. According to NSW Police’s Class 2 licence page, a Class 2C Security Equipment Specialist licence covers selling, installing, maintaining and repairing electronic security equipment such as CCTV cameras and alarm systems. A self-employed operator also needs a master licence. Ask any installer to show both.
If the alarm needs a new power point or hardwired power, that part needs a licensed electrician. If it connects to data cabling fixed in the building, that cabling must be done by a registered cabler under the ACMA cabling rules.
Planning tips for Inner West homes
- Cover the entry points: front door, back door, rear lane gate and any ground-floor windows.
- Use internal motion detectors in the hallway that leads to bedrooms, so an intruder is detected whichever way they come in.
- Mount the siren high and visible, as a deterrent.
- Combine with lighting: sensor lights at the back of the house deter intruders before they reach a window. See outdoor lighting.
- Add cameras at key points so you can check alerts. See security cameras for Inner West homes.
- Think about strata: in apartments, check by-laws for external sirens and common property.
Want to talk through an alarm for your home or business? See our alarms and security page or call 0421 772 661.
Cost factors
Alarm costs vary with:
- the number of sensors and zones
- wired vs wireless
- the panel and app features
- whether you add cameras
- monitoring fees, if you choose back-to-base
- whether an old system can be reused or must be removed
Ask for a written quote that lists every device, the monitoring arrangement and ongoing fees.
We help homes in Petersham, Croydon, Leichhardt and Haberfield.
Frequently asked questions
Is a wired or wireless alarm better?
Both work well. Wired systems avoid sensor batteries and suit renovations. Wireless systems are faster to install in finished homes. Many homes use a mix.
Do I need back-to-base monitoring?
Not necessarily. Self-monitoring through an app suits many households. Back-to-base adds a professional response for an ongoing fee.
Does an alarm installer need a licence in NSW?
Yes. Installing and servicing alarms is a licensed security activity. Installers need a Class 2C licence, and a self-employed operator also needs a master licence.
Will my pet set off the alarm?
It can. Pet-friendly motion detectors and careful sensor placement reduce false alarms.