Reducing overheating in homes

MBIE will take a staged approach to strengthening how the Building Code and its supporting documents address overheating.

New technical methodology for designers in 2026

MBIE will release a new technical methodology as voluntary guidance by the end of 2026, to encourage overheating risks to be considered early in the design process.

The methodology will provide designers with a consistent way to assess and manage overheating risks in new homes.

Building Code changes planned from 2027

Subject to the appropriate Ministerial and Cabinet decisions, changes will be made to the Building Code to support new compliance requirements for overheating. These changes will enable the technical methodology to be developed into a Verification Method in 2027.

The Verification Method will provide a voluntary pathway for demonstrating compliance. Where it is used, Building Consent Authorities will be required to accept it as a means of demonstrating compliance.

As part of MBIE’s 2031 Building Code update, MBIE is also planning a broader, more holistic approach to managing overheating, looking at how relevant performance requirements work together across the Building Code.

MBIE will work with the sector to ensure the changes are practical, proportionate and workable for designers, builders and councils.

Practical educational support for homeowners 

Alongside these technical changes, MBIE is working in partnership with Consumer NZ to provide practical information this summer to help homeowners understand and manage overheating in their homes.

This will include information on reducing heat build-up, and ventilation and cooling options.