Insulation and smoke alarms regulations

Ensure your rental makes the grade.

16feb insulation and smoke alarms hero

Rental properties are set to become slightly warmer, drier and safer, under proposed changes to tenancy laws. While the changes, which focus on insulation and smoke alarms, are a start, we don’t think they adequately address our problem with cold, damp homes.

The Residential Tenancies Amendment Bill was introduced last year after two deaths linked to unhealthy rentals led to renewed calls for a housing warrant of fitness. Once the bill is passed, rental properties will need to comply with the smoke alarm rules and some of the insulation rules from 1 July this year.

We’ve examined the proposed regulations to show what you need to do to ensure your rental makes the grade, and provided our best-practice smoke alarms and insulation advice. The regulations, which cover exactly how much insulation and how many smoke alarms are required, are being finalised by the Ministry of Business, Employment and Innovation.

Smoke alarms

Under the proposals, rental properties require a working smoke alarm in the hallway within three metres of every bedroom, and on every level in multi-level homes.

This stops short of Fire and Emergency New Zealand’s recommended practice of placing a smoke alarm in every bedroom, hallway and living area, on every level in the house. We suggest an alarm be fitted in every bedroom and hallway at a minimum.

The proposed regulations also require the use of long-life (10 year) photoelectric alarms. We support this requirement, as our smoke alarm testing shows ionisation alarms are hopeless at detecting smouldering fires – a potentially fatal failing.

To find out which smoke alarms we recommend, see the full results of our smoke alarms test.


By July 2019, all rentals will be required to have underfloor and ceiling insulation, as long as it can be practically installed.

From July this year, the bill also requires:

  • all new tenancy agreements to include a statement on the extent and safety of insulation
  • any repair or installation of insulation in a rental to meet the required standard
  • all social houses where a tenant pays an Income Related Rent to have underfloor and ceiling insulation where it can be practically installed.

While this is a positive step, we’re concerned these regulations don’t go far enough and potentially leave a significant number of rentals with inadequate insulation.

The proposed regulations permit untrained installers to install foil insulation underfloor. There’s a risk of electrocution when fitting it near exposed electrical wiring.

A major concern with the proposed regulations is they permit untrained installers to install foil insulation underfloor. Foil conducts electricity, so there’s a risk of electrocution when fitting it in floor spaces near exposed electrical wiring. It’s also less effective and reliable than bulk insulation underfloor, as its performance depends on the quality of its installation, which can be difficult for amateurs to get right. To make matters worse, its performance can severely degrade over time as the foil becomes ripped, which isn’t an issue with bulk products.

The regulations exempt homes where “it would be very costly and disruptive to insulate”. For example, flat-roofed houses where retrofitting insulation would require the removal of cladding or skillion-roofed houses lacking an adequate roof cavity. As a trade-off, we think landlords of exempt properties should be required to compensate by installing a fixed, efficient form of heating, like a heat pump or woodburner.

We recommend installing bulk underfloor insulation that’s designed to be fitted under suspended floors, and with an R-value of at least 1.4. It’s essential the insulation is the right width to fit between floor joists, and installed flush against the underside of the floor.

In ceilings, we recommend bulk insulation, which can be either blankets or segments. Be cautious with loose-fill insulation blown into the ceiling, as its performance can degrade as it settles or bunches up over time.

Insulation and smoke alarms regulations - Table

[width=35%] Ceiling[width=13%] Walls[width=13%] Underfloor[width=13%] Glazing[width=13%] Skylights[width=13%]
Zones 1 & 2 minimum - North Island excluding the Central Plateau R2.9 R1.9 R1.3 R0.26 R0.26
Zone 3 minimum - South Island and the Central Plateau R3.3 R2.0 R1.3 R0.26 R0.31

GUIDE TO THE TABLE Construction R-values show heat retention performance based on the combination of building components, including framing and the insulation itself. Table is based on Clause H1 – Energy Efficiency in the New Zealand Building Code: Acceptable Solutions for non-solid (timber-framed) construction. Higher R-values are required of ceilings for alternative construction methods.

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