Making our buildings more energy efficient

On 29 November 2021, The Ministry of Business, Innovation and Employment released the biggest energy efficiency changes to the Building Code acceptable solutions and verification methods in more than a decade.

These updates will allow people to heat their homes more easily and efficiently, making them more comfortable and healthier to live in as well as providing health benefits and energy savings to New Zealanders. Minimum insulation requirements for new building work are increasing for roofs, windows and floors. The updates aim to reduce energy needed to heat and cool new buildings by 23 per cent and to heat new homes by up to 40 per cent.

About the changes: • Six new climate zones are being established to reflect the specific weather experienced in different parts of

New Zealand. Each zone has specific minimum insulation requirements, meaning homes will need to be designed and built for the climate they’re located in. • Minimum requirements for roof insulation levels are doubling across the country. This is because roof insulation is one of the simplest and most cost effective ways to boost thermal performance. • Windows represent the largest source of heat loss in homes. The minimum insulation levels for windows are being increased across the country, with a focus on higher upgrades in those colder climate zones. • For underfloor insulation, higher floor insulation levels will be required generally, but further time has been allowed for slab-on-ground construction practices to change. • A new verification method for the energy efficiency of HVAC systems has been introduced to simplify the process for demonstrating compliance with the Building

Code. Creating this pathway will allow building owners to better monitor the performance of their HVAC system and know that the system is using energy optimally. • Suitable daylight solutions for buildings over three stories have been developed. New acceptable solutions and verification methods will ensure homes and buildings have sufficient amounts of daylight for the people who occupy them as outlined in the Building Code. • A test method for Verification Method E2/VM2 that can be used to demonstrate that cladding systems are sufficiently weathertight has been revised. The new version does not significantly change the minimum performance requirements and existing tested cladding systems will not need to be retested. This update is being made following a consultation process that received more submissions than the last five years of Building Code updates combined. MBIE received overwhelming support for the insulation changes from all parts of the sector including residential homeowners and tenants, with over 98 per cent of all responses supporting increases in the shortest time possible. Feedback on the Building Code typically comes from the various parts of the construction sector. A number of responses also came direct from the public – building owners, occupants and renters – reflecting the high levels of public interest in improving the energy efficiency of the homes we build.

There will be a one-year transition period for the sector to understand and prepare for the changes before they become mandatory in 2022. However, new window insulation requirements in the warmest climate zones will see a two-step approach with an interim increase in the next year and an additional increase in the following year. By the end of 2023, all parts of the country will have a similar minimum level of window insulation requirements.

Image taken by Erica Sinclair and purchased via www.truestock.co.nz, by MBIE.

For more information on the upcoming changes to the Building Code, and to sign up to get the latest information and updates from us visit www.building.govt.nz

Ministry of Business, Innovation and Employment. MBIE is the over-arching regulator of New Zealand’s building system. Our Building System Performance (BSP) branch provides policy and technical advice on New Zealand’s building system, rules and standards, and implements building legislation and regulations to meet New Zealand’s current and future needs.