Still relying on ionisation smoke alarms in your home? It may be time for an upgrade. Ionisation alarms were once the standard, but they’ve now been largely replaced by photoelectric smoke alarms, which offer faster response times to common household fires — and far fewer false alarms.
In this guide, we’ll explain the key differences between ionisation and photoelectric alarms, why it matters for your safety, and how to upgrade your system with ease.
What’s the Difference Between Ionisation and Photoelectric Smoke Alarms?
Ionisation smoke alarms use a small amount of radioactive material between two electrically charged plates to detect smoke. They respond quickly to fast-flaming fires (such as a fire in a rubbish bin), but are often slow to respond to smouldering fires — which are far more common in New Zealand homes.
Photoelectric smoke alarms, on the other hand, use a light sensor to detect smoke particles. They are especially effective at sensing smouldering fires, such as:
- Electrical faults
- Upholstery or mattress fires
- Overheating appliances
- Slow-burning kitchen fires
These are the types of fires that can fill a home with dangerous smoke before flames ever appear — making early detection critical.
Why Upgrade Ionisation to Photoelectric?
Upgrading to photoelectric alarms isn’t just about new technology — it’s about better protection.
Here’s why photoelectric alarms are the recommended standard:
- Faster response to smouldering fires (the most common and dangerous in homes)
- Fewer false alarms from cooking smoke or steam
- No radioactive components, making them safer to handle and dispose of
- Backed by NZ Fire and Emergency recommendations
If your current alarm doesn’t say “photoelectric” on the label, chances are it’s an ionisation model — and may already be nearing the end of its lifespan.
How Long Do Ionisation Alarms Last?
Most smoke alarms have a recommended lifespan of 10 years. After that, the sensors degrade, and the device may not respond effectively in an emergency.
If your alarms are:
- Over 10 years old
- Showing signs of yellowing or wear
- Beeping randomly despite new batteries
…it’s time to consider a full upgrade — and photoelectric is the smart choice.
How to Upgrade: Step-by-Step
Upgrading doesn’t have to be a hassle. Here’s a simple path to follow:
1. Identify Existing Alarm Types
Check the back or inside of the alarm for labels like:
- “Ionisation”
- “Contains radioactive material”
- Or a radiation symbol
If you see any of these, it’s an ionisation model.
2. Check Expiry Date
Many alarms have a manufacture or expiry date stamped on the unit. If it’s over 10 years old, it should be replaced immediately.
3. Choose a Modern Photoelectric Alarm
Look for reliable brands like CAVIUS, who specialise in photoelectric smoke alarms designed for New Zealand homes. Cavius alarms are compact, stylish, and come with advanced sensing to reduce false alerts.
You can also choose between:
- Standard smoke alarms (for bedrooms, hallways, lounges)
- Heat alarms (for kitchens, laundries, garages — where smoke alarms are prone to false alerts)
- Interconnected alarms, which communicate wirelessly across rooms
4. Replace or Retrofit
You can either:
- Remove and replace battery-powered alarms yourself (most are surface-mounted)
- Get professional help for hardwired systems or multi-alarm setups
Always follow manufacturer instructions, and test each alarm after installation.
Where Should You Place New Alarms?
For optimal protection:
- Install at least one alarm in every bedroom
- Place alarms in hallways and living areas
- Use heat alarms in kitchens and garages
- Ensure alarms are mounted on the ceiling, away from corners or vents
Want more help with placement? Check out our blog for setup and installation guides tailored for Kiwi homes.
Why Choose Cavius Photoelectric Smoke Alarms?
Cavius alarms aren’t just reliable — they’re thoughtfully designed for modern homes:
- Advanced photoelectric sensor reduces false alarms
- 5-year long-life batteries included
- Compact Scandinavian design
- Wireless interconnectivity for multi-room alerts
- NZ-compliant and easy to install
You’ll get peace of mind knowing your home is protected by industry-leading alarm technology.
Ready to Upgrade?
Don’t wait for your old alarm to fail. If you’re still using ionisation models — or your alarms are past their prime — make the switch to safer, smarter photoelectric smoke alarms today.
Browse our full alarm range and protect your home with confidence.
