2021 Building Code update

Outcome of the 2021 Building Code update

The Ministry of Business, Innovation and Employment (MBIE) updated acceptable solutions and verification methods to make new builds warmer, drier and healthier.

This update was made following a consultation that received more than 700 submissions totalling 3000 responses and more than 600 pages of feedback. This was more than the previous five years of Building Code consultation responses combined.

A summary of the decisions is provided below but we encourage you to read the outcome document for additional information on the feedback we received and the decisions themselves.

On 2 December 2021, MBIE hosted a webinar to discuss the final decisions from the 2021 update.

Watch the 2021 Building Code Update webinar recording - zoom.us

Summary of decisions

1. Energy efficiency for housing and small buildings

MBIE changed the roof, window, wall and underfloor insulation requirements by issuing the new edition of Acceptable Solution H1/AS1 and Verification Method H1/VM1 for housing and small buildings. The new insulation requirements aim to reduce energy needed for heating residential homes of approximately 40% over minimum previous requirements.

2. Energy efficiency for large buildings 

MBIE changed the roof, window, wall and underfloor insulation requirements and issued the new H1/AS2 and H1/VM2 for large buildings. This aims to reduce the energy needed for heating and cooling of 23% on average across new large buildings over previous minimum status quo requirements. 

3. Energy efficiency for heating, ventilation and air conditioning (HVAC) systems in commercial buildings 

MBIE published the new verification method H1/VM3 with modifications to the proposed text to clarify the requirements and address items raised in the consultation. This new verification method allows building owners to better monitor the performance of their HVAC system and know that the system is using energy optimally.

View the new acceptable solutions and verification methods for H1 Energy Efficiency

4. Natural light for higher-density housing 

MBIE published the new acceptable solutions G7/AS1 and G7/AS2 with minor modifications to the proposal. The existing outdated G7/VM1 was replaced with a verification method to demonstrate compliance using computer modelling. Refreshing these acceptable solutions and verification methods for clause G7 Natural Light helps ensure people have sufficient amounts of daylight in higher-density housing.

View the new acceptable solutions and verification methods for G7 Natural Light

5. Weathertightness testing for higher-density housing 

MBIE issued the new edition of E2/VM2 without any modifications to the proposal.  The revised weathertightness testing method cited in E2/VM2 can be used to demonstrate that cladding systems are sufficiently weathertight. The new version does not significantly change the minimum performance requirements and existing tested cladding systems will not need to be retested.

View the new Verification Method E2/VM2 

6. Standards referenced in B1 Structure 

MBIE referenced the new versions of four standards in the acceptable solutions and verification methods for B1 Structure.

7. Editorial changes to Acceptable Solution B1/AS1 

MBIE made editorial corrections to Acceptable Solution B1/AS1 without any modifications to the proposal.

View the new acceptable solutions and verification methods for B1 Structure

Transition period

The new acceptable solutions and verification methods were effective on 29 November 2021 and the transition period for the documents ended on 2 November 2022. The previous versions of the documents can no longer be used to demonstrate compliance with the Building Code.

Additionally, in July 2022, MBIE announced a six month extension to the transition period for the insulation requirements in new housing. The new acceptable solutions and verification methods for H1 contain provisions to use lower R-values for housing until 1 May 2023. The new window insulation requirements in the warmest climate zones will see a different approach with an interim increase in May 2023 and an additional increase in November 2023. This means by the end of 2023, all parts of the country will have a similar minimum level of window insulation requirements. 

Read a summary of the extension to the transition period and the outcome document.

Building and construction sector climate change response timeframes

The 2021 consultation, we heard that there is uncertainty about how the Building Code would address climate change in future.

The outcome document discusses the building and construction sector climate change response and provides a diagram that shows the high-level timeframe for this response. Additional information is provided in the discussion on the energy efficiency changes.

We encourage you to read the outcome document for more information on how future updates to the Building Code will continue to focus on reducing carbon emissions.

Read more about the MBIE Building for Climate Change Programme

Outcome of the operating protocols consultation

MBIE published two new operating protocols to provide increased transparency and certainty about the activities MBIE undertakes as stewards of the Building Code. The protocols outline how MBIE references standards in the Building Code system and supports the development of standards.

Read the operating protocols on standards

These protocols were published following consultation in 2021. The feedback from the consultation emphasised the importance that standards have in the building system and the desire for strategies to be in place across all building-related standards to ensure their upkeep. MBIE are committed to working with the sector and Standards New Zealand to address these issues strategically to ensure we have plans in place across the range of standards referenced in the Building Code.

MBIE considers that the process of developing and consulting on operating protocols has been useful to help generate discussion, increase transparency and identify any issues that need further work.

Please read the outcome of consultation on the Building Code operating protocols for more discussions on the feedback we received and the revisions we made from the proposals. 

Earthquake geotechnical engineering practice series

As part of the 2021 update, MBIE re-issued the guidance documents "Earthquake geotechnical practice series (Modules 1 - 6)" under section 175 of the Building Act.

These modules were developed alongside the New Zealand Geotechnical Society and Engineering New Zealand and were first published in 2016 and 2017.

The updated guidance documents address feedback received from the geotechnical sector and ensure that they continue to be regarded as the current, credible references for geotechnical design of buildings

Read the geotechnical guidance

Background on the consultation

The consultation on the 2021 update ran between 6 April and 28 May 2021.

View the 2021 Building Code update consultation document - mbie.govt.nz

On 21 April 2021, Building Performance held a webinar to discuss the proposed changes.

Watch the Building Code Update Consultation webinar - Zoom

For those who attended the webinar, there were some questions which we didn't get to on the day. We have been through the comments and questions and provided information below.

Background reports on H1 Energy Efficiency

Several participants in the webinar asked for further details on the analysis of insulation requirements, to expand upon the information provided in the consultation document.

To provide further background on the proposals for consultation, we have provided copies of reports commissioned by MBIE on this topic. These reports were produced by BRANZ and Beca and provided information on the thermal modelling and cost benefit analysis for determining the R-values in the consultation document.

Read the BRANZ report [PDF 10.4MB]

Read the Beca report [PDF 6MB]

These reports provided a solid foundation for us to consider the implications for the design of new buildings in New Zealand. However, for more information on the regulatory context and other factors to consider for these proposals, we encourage you to review the consultation document.

Building Code regulations

The annual Building Code update provides a predictable timeline for consultation and publishing new material to support compliance with the Building Code. This can include all parts of the Building Code system including the Building Code regulations (the 41 Building Code Clauses), acceptable solutions, verification methods and guidance information.

This year, there are no changes proposed to the Building Code regulations. However, a review of the current performance clauses for H1 Energy Efficiency, G5 Interior Environment and G6 Airborne and impact sound is currently in progress.

View the Building Code regulations - legislation.govt.nz

Current and future work programme to update the Building Code

Climate zones

The changes to climate zones will better reflect specific weather in different parts of New Zealand and will no longer be "one size fits all". Our aim in making these updates is to make sure homes and buildings are more suited to the climate where they are being built.

The six climate zones are based on thermal modelling of buildings using NIWA climate data files for 18 different climate stations. These climate stations were previously selected by NIWA to represent the different climates experienced around New Zealand. The climate zone boundaries also take into consideration territorial authority (local government) boundaries to make it easier to follow and understand what requirements apply to the different parts of the country.

There will always be exceptions to the site specific conditions of a building so the modelling methodology in the H1 Energy Efficiency verification methods H1/VM1 and H1/VM2 to allow for adjustments for local conditions and project specific concerns.

Insulation R-values

The proposed R-values in the consultation document are construction R-values for roofs, walls, floor and windows. This is detailed in the draft acceptable solution and verification methods in the appendix of the consultation document. For example, H1/AS1 Subsection 2.1.4 describes the method for determining the thermal resistance of building elements and can be found on page 69 of the consultation document.

Insulation values from other countries are shown in the consultation document as a tool to illustrate that current New Zealand requirements are behind international standards with similar climates to New Zealand. Some people have commented on the values used to compare for England, Wales and Ireland.

For England and Wales, the values we've shown in the consultation document are the absolute minimum requirements for those countries. We chose to use these values to provide more of a fair comparison, and to be sure we are not overstating their performance.

Ireland now has higher performance standards than the values we show in the consultation document because our source document has been superseded by an updated version with Ireland’s requirements now going further.

High thermal mass walls

Allowances for higher thermal mass walls is proposed to be removed the Acceptable Solution H1/AS1. This is discussed in the consultation document in Section 1.4.6 "Other changes within H1/AS1 and H1/VM1". Verification Method H1/VM1 provides a better and fairer way to determine how much insulation is required for these types of buildings. Designers of buildings with high mass walls would still have the option of using the simpler compliance methods of H1/AS1 but without any special treatment of buildings with high mass walls.

The extent to which high mass walls can help reduce the amount of heating and cooling energy required to maintain comfortable indoor temperatures depends on a number of factors. For example, the density and thickness of the materials that the walls are made from, the size of these walls, whether the insulation is placed on the interior or exterior side of the walls and the extent to which the interior surfaces of the high mass walls are exposed to direct sunlight. Thus, the energy efficiency benefits of homes and buildings with high mass walls are best assessed through computer thermal modelling.

Airtightness, infiltration and thermal bridging

MBIE is monitoring other aspects that impact energy efficiency and a building's internal environment, and will work to resolve any issues in future Building Code updates such as airtightness and thermal bridging.

Residential building types

Energy savings and investment figures which are provided for Proposal 1: Energy efficiency for housing and small buildings are based on a detached single-storey house as this is predicted to remain the most popular building type in New Zealand.

Multi-unit dwellings such as apartments are included in Proposal 1 in the Building Code consultation document. The way multi-unit dwellings are used by their occupants is similar to other residential building types and different to large non-residential buildings such as office buildings. Therefore, multi-unit dwellings are proposed to be covered by the same energy efficiency requirements as all housing. MBIE is aware that the thermal characteristics of apartments is different to low-rise detached homes. The Building for Climate Change programme proposes to introduce a more holistic framework for different building shapes and typologies.