The new requirements for large buildings aim to reduce the emissions and energy used when heating and cooling a larger building by 23% on average over previous minimum status quo requirements.


This overview of changes applies to ‘Buildings greater than 300m2’, including but not limited to buildings classified as offices, retail, schools, hotels, restaurants, etc. The specified area – greater than 300m2 – is based on the occupied space of the building.


These changes only affect new construction or existing properties undergoing changes to the external thermal envelope, which will require a building consent.


Industrial buildings are not currently required to be energy efficient so sit outside the scope of this work. However, if there was an office within a warehouse, or an industrial building, that office would have to comply with the updated requirements.

What’s changed?

MBIE changed the roof, window, wall and underfloor insulation requirements for buildings larger than 300m2. These changes are outlined in the table below.

Increases in minimum R-values for large buildings

Options Climate Zone
1 2 3 4 5 6
Roof R3.5 R4.0 R5.0 R.5.4 R6.0 R7.0
Windows R0.33 R0.33 R0.37 R0.37 R0.40 R0.42
Wall R2.2 R2.4 R2.7 R3.0 R3.0 R3.2
Slabs R2.2 R2.2 R2.2 R2.4 R2.5 R2.6

Compliance Pathways

Acceptable Solutions

There are different ways to show that a building complies with the Building Code.


One way is through the use of acceptable solutions or verification methods. To meet the increased insulation requirements of H1 Energy Efficiency in buildings more than 300m2, MBIE updated H1/AS2 and H1/VM2.


The new editions of Acceptable Solution H1/AS2 and Verification Method H1/VM2 aim to:

1. Lift minimum levels of insulation for large buildings to make them more comfortable and easier to heat and cool.


2. Introduce a new climate zone map to better recognise variations in climate around New Zealand, and reflect this in the proposed requirements.


3. Provide a clear compliance pathway for these buildings by separating the requirements for large buildings into their own acceptable solution and verification method.

Verification Methods


The verification methods for H1 (H1/VM1 & H1/VM2) contain rules for design professionals to use computer modelling and software to determine the minimum amount of insulation required in a building and to demonstrate compliance with the Building Code. Only H1/VM2 can be used for ‘Buildings over 300m2’.


This acceptable solution can be used for larger buildings with an area of occupied space more the 300m2. It does not include provisions for housing. To determine the minimum insulation requirements, this document contains two methods – Schedule and Calculation.



This verification method can be used for larger buildings with an area of occupied space more the 300m2. It does not include provisions for housing. Unlike H1/VM1, there are no limitations on the type of construction elements and specific designs the document covers for these buildings.


The method used to determine the minimum insulation requirements is based on computer modelling and known as the Modelling method. Users of this method are expected to have specific training and expertise to conduct the simulations.

Alternative solutions

If designers or builders want to comply with the Building Code performance requirements directly, they may also choose to use an alternative solution as a compliance pathway.


This will usually require specific design and input from suitably qualified people, such as architects or engineers. Alternative solutions are not deemed to comply with the Building Code and must be assessed by the relevant Building Consent Authority on their individual technical merits.


For the insulation requirements, the alternative solution must satisfy the Performance Criteria in clause H1.3.1(a)