Smoke alarms save lives, and in New Zealand the rules around which type you must have — and where — have become much clearer in recent years. Whether you're a homeowner, landlord, or tenant, understanding the requirements helps keep your household safe and keeps you on the right side of the law.
The Legal Requirement: Photoelectric Smoke Alarms
Under the Residential Tenancies (Healthy Homes Standards) Regulations and broader NZ building and fire safety guidance, all residential properties must be fitted with photoelectric smoke alarms. Ionisation-type alarms — once the most common type sold in NZ — are no longer acceptable as a replacement when alarms need upgrading.
Why photoelectric? Photoelectric alarms use a light beam to detect the larger smoke particles produced by slow, smouldering fires (the most common type in homes). They are less prone to nuisance alarms from cooking and generally respond faster to the kinds of fires that cause the most fatalities.
You can read more about the Healthy Homes Standards, including smoke alarm requirements for rental properties, on Tenancy Services.
Long-Life vs. Replaceable Battery Alarms
NZ regulations require that smoke alarms have a long-life power source — either:
- A sealed, non-removable 10-year battery, or
- Hardwired (230V mains power) with a battery backup
Standard 9V battery alarms are no longer compliant for new installations in rental properties, and are not recommended for owner-occupied homes either. Long-life alarms reduce the risk of a flat battery leaving you unprotected.
| Alarm Type | Power Source | Compliant for NZ Rentals? | Notes |
|---|---|---|---|
| Photoelectric, 10-year sealed battery | Battery (long-life) | ✅ Yes | Most common DIY-install option |
| Photoelectric, hardwired | Mains + battery backup | ✅ Yes | Must be installed by licensed electrician |
| Ionisation, any power | Battery or mains | ❌ No | Cannot be used as replacement |
| Standard 9V battery photoelectric | Replaceable battery | ❌ No | Not compliant for rentals |
Where Do Smoke Alarms Need to Be Placed?
Placement matters as much as alarm type. The requirements are:
- At least one alarm on each level of the home (including basement and attic if habitable)
- In every bedroom, or in the hallway or area outside sleeping areas
- In the main living area (e.g. lounge or open-plan living/kitchen space)
- Alarms should be mounted on the ceiling, at least 300mm from any wall or light fitting, and away from corners where air circulation is poor
- Keep alarms at least 3 metres from cooking appliances where possible to reduce nuisance alarms
For multi-storey homes, BRANZ recommends interconnected alarms so that when one sounds, they all sound — giving occupants on every level early warning.
Interconnected Alarms: Are They Required?
Interconnection is not universally mandated for all existing homes, but it is best practice and is required in some new builds under the NZ Building Code. In new residential construction, Clause F7 (Warning Systems) of the Building Code sets out requirements for smoke alarm systems, and interconnected alarms are typically specified.
Interconnected alarms can be:
- Hardwired (linked by cable — requires a licensed electrician)
- Wireless/RF (radio-frequency linked — can often be DIY installed)
Wireless interconnected photoelectric alarms with 10-year batteries are widely available at Bunnings and Mitre 10, and are a practical upgrade for most homes.
What Can a Homeowner Install Themselves?
This is where the electrical rules matter. In New Zealand:
- Battery-operated smoke alarms (including long-life sealed battery models) can be installed by any homeowner — no licence required. Simply screw the base to the ceiling and click the alarm in.
- Hardwired smoke alarms connect directly to your home's 230V mains wiring. This is restricted electrical work and must be carried out by a registered electrician licensed with the Electrical Workers Registration Board (EWRB).
Attempting to connect or modify mains wiring yourself is illegal and dangerous. Always use a qualified sparky for any hardwired installation.
When to Call a Professional
You'll need a licensed electrician if you want to:
- Install or replace hardwired smoke alarms
- Set up a hardwired interconnected alarm system
- Upgrade an older hardwired system to meet current standards
- Integrate smoke alarms with a home security or fire panel
A registered electrician will also issue you a Certificate of Compliance (CoC) for the work, which is important for insurance and any future property sale. You can find qualified local electricians on tradedirectory.co.nz.
Safety note: Test your smoke alarms monthly using the test button, and replace any alarm that is more than 10 years old — even sealed-battery models have a finite sensor lifespan.
Landlord Obligations
If you rent out a property, compliance with the Healthy Homes smoke alarm standard is compulsory. Landlords must ensure:
- All alarms are photoelectric with a long-life power source
- Alarms are in working order at the start of each tenancy
- The required number and placement of alarms is met
Non-compliance can result in a financial penalty. Check the current standards on Tenancy Services or seek advice from MBIE Building Performance.