Residential building consent applications submitted after 3 November 2022 may need to meet increased window performance requirements required by the building code under recent amendments to clause H1: Energy efficiency.

This is the first of a 2-step transition that increases requirements. The second transition on 1 May 2023 will complete the full changeover of increased performance requirements which include increased performance requirements for insulation to windows, ceilings, and floors.

More information on these changes can be viewed on the MBIE Building Performance website.

What does this mean for my residential application?

The new requirements apply to applications received by Council on or after these dates.

Your increase in the performance requirements for windows and skylights changes from R0.26 to R0.37 if you nominate H1/AS1 (acceptable solution) as your means of compliance.

Refer Table schedule method H1/AS1 5th edition, amendment 1 for the schedule method, and calculation method, when the proposed window R-value is R0.26 and above.

To demonstrate compliance for limiting energy use you will now need to increase the window performance, which is:

  • compulsory under the schedule method, or
  • optional under the calculation method where you will need to increase insultation within other parts of the building if you are unable to increase the window performance referenced in the schedule table of the transition table above (which is in effect from November until May).

Note that H1/AS1 is for all housing, and buildings other than housing less than 300m2.

The minimum construction types for vertical window frames, and the components of the insulated glass units (IGU) to achieve the required minimum R0.37 (schedule method) are identified on Table E.1.1.1 of H1/AS1.

Because the components of the IGU aren’t visible at the time of inspection (ie IGU spacer, IGU gas, and low-E glass) to achieve the minimum of R0.37 (refer table above), we will require the following documentation with your application and at inspection:

Building consent application

A detailed specification that identifies:

  • window frame type,
  • IGU spacer type,
  • IGU glass type, and
  • IGU gas type.

During construction at the inspection and CCC stages

  • Documentation from the window supplier confirming that the windows have been supplied and installed to the specification within the consented documentation
  • These will be listed as required documents on the building consent Form 5.