What are the proposed changes?

We are proposing changes to increase the range of compliance options available for apartment buildings1 (Class 2 buildings) with centralised heated water systems.

More information on these proposed changes is in Table 1.

1 The changes are also proposed for a Class 4 part of a building.

Why are these changes proposed?

Currently, if a centralised heated water system is present, practitioners cannot use either the Deemed-to-Satisfy (DTS) elemental or the Nationwide House Energy Rating Scheme (NatHERS) compliance pathways. Instead, practitioners must use J1V5 or another Performance Solution to demonstrate compliance with Performance Requirement J1P3.

How were the changes developed?

We engaged a technical consultant to research and develop DTS elemental provisions for centralised systems that provide heated water for sanitary purposes.

The research found that it was possible to amend J3D14 to accommodate centralised heated water systems by:

  • modifying the current J3D14 methodology for the net equivalent energy usage for a standalone system
  • considering characteristics such as water heater conversion efficiency, circulation pump energy, and heat losses associated with storage and distribution.

Who’s been involved?

We engaged a technical consultant to develop additional DTS elemental provisions for centralised heated water systems. We also consulted with the BASIX and NatHERS teams within the NSW Government and the Commonwealth Department of Climate Change, Energy, the Environment and Water (DCCEEW) respectively.

We also consulted with members of our peak technical committee, the Building Codes Committee.

What are the impacts?

These changes will make it easier for apartment buildings served by centralised hot water systems to demonstrate compliance with the NCC. This should improve the range of options available to building designers and reduce administrative costs.

The proposed changes will not impact the stringency level of the energy efficiency provisions for apartment buildings.

To read the full details of the changes, please review the NCC 2025 Volume One PCD and Section A.

Want to provide feedback?

Responses to the Public Comment Draft are invited until 11:59 PM AEST Monday 1 July 2024.

In line with the ABCB's process for undertaking public consultation, comment will only be accepted through the ABCB's online Consultation Hub.

To access the Public Comment Draft and response form:

  1. Download the NCC volume(s) you wish to view and provide comment. You can also download the supporting information PDF for detailed information on the more significant/complex changes.
  2. Download the response form.

Once you’ve reviewed the draft, complete the response form, and include your feedback on the suggested changes to the NCC.

To submit your comments:

  1. Enter our Public Comment Draft consultation hub.
  2. Start by agreeing to the privacy statement.
  3. Let us know if you’d like your submission published publicly.
  4. Enter your contact details.
  5. Upload your completed form in .doc format (please make sure each file is under 25MB) and submit.

Table 1: Proposed changes to DTS Provision D3J14 of Volume One for the next edition of the NCC

Clause Number (NCC 2022) Clause Number (next edition)Proposed changes




Clause J1D14(1) is proposed to be restructured, with its requirements now separated and included in three different clauses (J3D14(1), J3D14(2), J3D14(3))
 J3D14(4)(New)A new method proposed to calculate the net equivalent energy usage of a sole-occupancy unit (SOU) of a Class 2 building or Class 4 part of a building served by a centralised heated water system.

Updates to clause numbering

Amendment proposed to clarify that the method to determine the swimming pool pump energy usage (Ep) applies exclusively to the swimming pool dedicated to an SOU of a Class 2 building or Class 4 part of a building

J3D14(3)J3D14(6)Updates to clause numbering
 J3D14(7)(New)A new method proposed to determine the main space conditioning and main water heater efficiency factor for an SOU of a Class 2 building or Class 4 part of a building
 J3D14(8)(New)A new method proposed to determine the circulating pump energy usage