If you're looking at defibrillators for your workplace, you'll notice they come in two types: semi-automatic and fully automatic. Both do the same job. Both save lives. The difference is one small step in the process, and it's worth understanding before you choose.
The one difference that matters
With a semi-automatic defibrillator, the device analyses the heart rhythm, decides whether a shock is needed, and gives audible prompts telling everyone to stand clear. The rescuer then performs the final step — pressing the shock button to deliver it.
With a fully automatic defibrillator, the device does all of that on its own. It analyses, decides, provides audible warnings and a clear pause to ensure everyone is clear, then delivers the shock automatically. No button press required.
That's it. Same analysis. Same shock. Same outcome. The difference is whether a person needs to press a button or not.
So which one should you choose?
It depends on who's most likely to use it.
Choose fully automatic if:
- Your workplace has staff with no first aid training (or minimal training)
- The defibrillator will be in a public-access location like a reception area, foyer, or community space
- You want to remove any chance of hesitation during a high-stress moment
- You're buying for a school, sports club, or community venue
In a real emergency, the biggest barrier isn't the technology. It's the moment of hesitation before pressing the button. The fully automatic G5 takes that decision away entirely, so the rescuer can focus on the person in front of them.
Choose semi-automatic if:
- Your workplace has trained first aiders or first responders on site
- You want the rescuer to have a moment to confirm everyone is clear before the shock is delivered
- Staff are comfortable with the idea of pressing a button during a rescue
- You're in a healthcare, mining, or emergency services environment where responders are experienced
Some trained responders actually prefer the semi-automatic because it gives them a sense of control. The device still prompts everyone to stand clear — the rescuer simply performs the final action themselves. For experienced users, that deliberate step can feel more intentional.
What about the G5 specifically?
The St John G5 is available in both models, and everything else about the device is identical. Both versions include:
- ICPR (Intellisense CPR) feedback that coaches you through chest compressions in real time, letting you know if you need to push harder or faster
- Australian voice prompts that guide you through every step clearly
- IP55-rated rugged build for dust and water resistance
- 8-year warranty and automatic self-testing so it's always rescue-ready
- 90 minutes of rescue data storage for clinical handover
The G5 is one of the few defibrillators on the market that provides real-time CPR coaching. This matters because the quality of CPR between shocks has a direct impact on outcomes. The device doesn't just shock. It helps you do better CPR.
One thing worth noting for ongoing readiness: track expiry dates for both your pads and battery. G5 pads have up to a 2-year shelf life, and the battery lasts up to 4 years. The G5's automatic self-testing will alert you if something needs attention, but it's good practice to know your dates.
A common concern: "What if someone uses it wrong?"
This is the question we hear most often, and it's a good one. The short answer: you can't shock someone who doesn't need it. Both the semi-automatic and fully automatic G5 will only deliver a shock if the device detects a shockable heart rhythm. If the rhythm is normal, or if the person is experiencing a type of cardiac event that doesn't require defibrillation, the device simply won't shock. It's built that way.
There's genuinely no risk of causing harm by using one. Having the confidence to act is the hardest part, and the G5 is designed to guide you through it.
What most of our customers choose
For workplaces without dedicated medical staff, the fully automatic is the most popular choice by a clear margin. Most buyers tell us the same thing: "If something happens, I want the device to do as much as possible."
That makes a lot of sense. In a cardiac emergency, every second counts. Removing the need to think about which button to press means the rescuer can focus entirely on helping the person.
Both the semi-automatic and fully automatic St John G5 are currently available at $1,950 as part of our EOFY sale (reduced from $2,450). If you want the complete setup including an outdoor cabinet, AED ready pack and signage, our G5 bundles start at $2,400.