How to Assess Whether Your Older Home Has Adequate Smoke Alarms

Smoke alarms save lives, but many older New Zealand homes were built before today's requirements existed — meaning they may have too few alarms, the wrong type, or units that are well past their use-by date. A straightforward walk-through assessment can tell you whether your home is up to scratch and what needs to change.

What the Law Requires in New Zealand

Since 1 July 2016, all residential properties in New Zealand must have working smoke alarms. The requirements are reinforced through the Residential Tenancies Act for rental properties. For rental homes, the Tenancy Services Healthy Homes standards specify that smoke alarms must be present in every bedroom, in every room where a person sleeps, and in every hallway or area between sleeping areas and the rest of the home. Owner-occupied homes are strongly encouraged to meet the same standard.

The key minimum requirements are:

• At least one working smoke alarm on each level of the home
• Alarms within 3 metres of each bedroom door (measured along the ceiling or wall)
• Long-life photoelectric alarms (with a 10-year battery) are required in new builds and recommended for all homes
• Alarms must not be more than 10 years old from their manufacture date

Step 1 — Count and Map Your Alarms

Walk through every level of your home and note where each smoke alarm is located. Draw a rough floor plan if it helps. Ask yourself:

• Is there an alarm on every floor, including the basement or sleep-out?
• Is there an alarm within 3 metres (along the ceiling path) of every bedroom door?
• Are there alarms in living areas and hallways that connect sleeping areas to exits?

Many older homes have only one alarm — often in the hallway — which is unlikely to be sufficient for a multi-bedroom or multi-storey house.

Step 2 — Check the Type of Alarm

There are two main types of residential smoke alarm:

Photoelectric alarms are now the recommended standard in New Zealand because most house fires start as slow, smouldering events — particularly at night. Check the label or back of your existing alarms to identify which type you have. If they are ionisation-only, consider replacing them with photoelectric units.

You can find photoelectric alarms at Bunnings or Mitre 10.

Step 3 — Check the Age and Condition

Smoke alarms have a maximum lifespan of 10 years. The manufacture date is usually printed on the back or base of the unit. If you cannot find a date, or the alarm is clearly old, replace it.

Also check:

• Is the test button working? Press and hold it — the alarm should sound within a few seconds.
• Is the alarm dusty or cobwebbed? Vacuum gently with a soft brush attachment.
• Is the battery indicator light functioning (for battery-powered units)?
• For hardwired alarms, is the green power light on?

If an alarm fails the test button check or shows signs of damage, replace it immediately.

Step 4 — Check Placement

Even correctly typed alarms won't perform well if they're in the wrong spot. Avoid placing alarms:

• In or directly outside kitchens (within 1.5 m of cooking appliances) — nuisance alarms are a common reason people remove or disable them
• In bathrooms or near steam sources
• In garages where exhaust fumes can trigger false alarms
• In corners where dead air can delay detection — mount on the ceiling at least 300 mm from any wall or corner

For sloped or cathedral ceilings, mount the alarm within 600 mm of the highest point.

Step 5 — Consider Interconnected Alarms

In larger or multi-storey homes, interconnected alarms are strongly recommended. When one alarm detects smoke, all alarms in the home sound simultaneously — giving everyone maximum warning time regardless of where the fire starts. Interconnection can be achieved with:

• Hardwired systems (requires an electrician — see below)
• Wireless/radio-frequency interconnected alarms (no wiring required, a DIY-friendly option)

BRANZ provides good guidance on best-practice smoke alarm installation for NZ homes.

Step 6 — Rental Properties: Additional Obligations

If your older home is a rental, you have legal obligations under the Healthy Homes Standards. Landlords must ensure alarms meet the type, placement, and age requirements, and must check them at the start of each tenancy. Refer to Tenancy Services for the full checklist.

When to Call a Professional

Hardwired smoke alarm installation or replacement is restricted electrical work under the Electricity Act and must be carried out by a registered electrician. You must not connect or disconnect hardwired alarms yourself. Check that any electrician you hire is registered with the Electrical Workers Registration Board (EWRB).

For a broader assessment of your older home's safety — including structural, weathertightness, and compliance matters — a licensed building inspector can provide a thorough report. You can find qualified local building inspectors and other tradespeople on tradedirectory.co.nz.

Safety note: Never remove or disable a smoke alarm, even temporarily. If nuisance alarms are a problem, relocate the unit or switch to a photoelectric type rather than removing it.

Sources & Further Reading

• Tenancy Services — Healthy Homes smoke alarm requirements
• BRANZ — Smoke alarms and fire safety guidance
• MBIE Building Performance — Building Code compliance
• WorkSafe NZ — Home fire safety
• EWRB — Find a registered electrician
• Standards NZ — NZ Standards for residential buildings