The new housing and small building insulation requirements are the same. The only difference between them is the transition date for the new final values to come into effect.


For ‘Buildings under 300m2’, the new requirements came into effect on 3 November 2002. For housing, the new requirements were pushed back for six months, meaning they come into effect on 1 May 2023.


The only exception is category is ‘windows and doors’, which retained its original two-stage implementation – with the first on 3 November 2022 and the second on 2 November 2023.

New compliance documents, old R-values?

Despite the extension for ‘Housing’, transition to the new compliance documents for ‘Housing’ and ‘Building under 300m2’ – the 5th editions of H1/AS1 and H1/VM1 – took place on 3 November 2022. This means the previous 4th editions of these documents can no longer be used for building consents.


The 5th editions of H1/AS1 and H1/VM1 include new methodologies for establishing the thermal resistance of windows, doors, skylights, curtain walling and slab-on-ground floors. From 3 November 2022, only the new methodologies can be used (with the exception of slab-on-ground floors).


However, until 1 May 2023, building consents for ‘Housing’ can use the “old” minimum construction R-values for roofs, walls and floors – those in the 4th editions of H1/AS1 and H1/VM1.


Minimum R-values for each building element for housing in H1/AS1 and H1/VM1

Options Climate Zone
1 2 3 4 5 6
Current minimum requirements R2.9 R2.9/3.3 R3.3
1 May 2023 R6.6
Current minimum requirements R1.9 R1.9/2.0 R2.0
1 May 2023 R2.0
Current minimum requirements R1.3
Slab-on-ground floors 1 May 2023 R1.5 R1.5 R1.5 R1.5 R1.6 R1.7
Other floors 1 May 2023 R2.5 R2.8 R3.0
Windows & Doors
Previous minimum requirements R0.26
3 November 2022 R0.37 R0.37 R0.37
1 May 2023 R0.37 R0.46 R0.50
2 November 2023 R0.46 R0.46 R0.50

It’s important to note that meeting these R-values is based on using the Schedule Method for compliance.  When using the Calculation or Modelling method, individual construction element R-values may be higher or lower depending on several variables.

H1 Energy Efficiency

The Building Code contains requirements for the energy efficiency of buildings. These are found in code clause H1 Energy Efficiency. This clause includes requirements for:

- Insulation

- Limiting uncontrollable airflow

- Hot water systems 

- Artificial lighting 

- Heating, ventilation and air conditioning (HVAC) systems

We are focusing on insulation requirements in buildings, which are found in code clause H1.3.1(a).


This clause applies to the building envelope that encloses spaces where the temperature or humidity are modified in a building (conditioned spaces). The building envelope is required to have adequate thermal resistance to resist the flow of heat from hot to cold.


Insulation is a barrier. It helps keep the heat in during the winter and can help keep the heat out during summer. This means that insulation is beneficial even in the warmest part of the country.


To be effective, the barrier has to be continuous in the building. That’s why the H1 changes look at insulating all parts of a building including ceilings, walls, floors, windows, doors and skylights.


Read more on how to meet the new construction R-values by click on each element in the image below.