Energy efficiency for residential buildings: Nathers heating and cooling load limits Consultation ris

C.4Option B - Non-Regulatory Option

Table Option B results

Building classification	Present Value of energy savings and external benefits	Present Value of construction cost savings	Net Present Value
Class 1	$2,834,000	$2,430,000	$5,264,000
Class 2	$1,419,000	$7,160,000	$8,579,000

The Consultation RIS concludes that Option A is expected to generate an additional $81.4 million in net benefits compared to Option B. On this basis the analysis favours Option A.

The Consultation RIS also proposes that the most effective means of implementing the heating and cooling load limits would be via a minor, one-off change to the NCC, publishing the load limits for transparency, and incorporating the load limits into NatHERS assessments for ease of use and to facilitate better compliance.

Appendix DOptions for heating and cooling load limits implementation

Successful implementation of the heating and cooling load limits needs to be carried out in consideration of the following criteria from the end user’s perspective: compliance burden, transparency and practicality.

Implementing the load limits should not impose an excessive compliance burden and complicate the compliance process. Including the heating and cooling load limits directly in the NCC is problematic for a number of reasons. It is inconsistent with, and complicates, the manner in which the NatHERS compliance pathway is prescribed. The NatHERS star ratings are referenced in NCC, but not the corresponding star bands/total energy loads. Typically, technical detail of this nature is included in NCC referenced documents. Another practical challenge for detailing the load limits in the NCC is due to the difference in climate zones. The NCC has 8 climate zones; whereas the heating and cooling load limits apply to the 69 NatHERS climate zones.

However, this does not mean no change should be carried out in the NCC. It is proposed that the clauses applicable to the NatHERS compliance pathway specify the need to meet the heating and cooling load limits, in addition to the overall star rating requirements. Reference would also be provided to where the applicable load limits can be found online, so that this information is discoverable. Proposed changes to NCC content can be found in the NCC 2019 Public Comment Drafts for Volumes One and Two.

Implementing the load limits using NatHERS accredited tools should also not impose an excessive compliance burden and complicate the compliance process. An automated system in the NatHERS software tools is proposed to filter results based on each dwelling’s profile, i.e. climate zone, building classification and floor types (on-ground or suspended); with the system showing the heating and cooling load limits that apply to the specific scenario.

This approach would overcome the need for assessors to have to interpret pages of tables and undertake calculations to determine a particular load limit, as this would be built into the software tool processes. Similarly, building certifiers will not need to interpret pages of tables, as the NatHERS Universal Certificate will show the applicable heating and cooling load limits alongside the calculated heating and cooling loads of the subject dwelling. In this instance, an automated system is far more efficient and accurate than use of traditional regulatory publications. Notably, New South Wales BASIX has an online system to automate its processes. Similarly, the current NatHERS system already automates the application of the total load star bands in the software tool processes and on the Universal Certificate.

The automation ‘rules’ for applying the heating and cooling load limits in NatHERS software tools are yet to be determined by the NatHERS Administrator for implementation by the NatHERS software tool owners.

Supporting material would also be developed to ensure the heating and cooling load limits are well communicated and explained.

Appendix EConsultation

The ABCB Energy Efficiency Project Residential Technical Workgroup (the Residential Working Group)¹⁰ was established at the beginning of the Energy Efficiency Project in mid-2016. The Residential Working Group members have been consulted during the development of the heating and cooling load limits, including the engagement of the consultant and development of the methodology for determining the load limits. An ABCB Board Steering Committee and the ABCB’s national Building Codes Committee have also been consulted throughout this process.

The ABCB has sought the feedback from the Office of Best Practice Regulation (OBPR) who have assessed the analysis as being prepared in accordance with COAG Guidelines and suitable for further consultation.

The ABCB Office is also seeking input from interested parties on the proposed technical changes to NCC 2019, including the proposed heating and cooling load limits. The NCC 2019 Public Comment Draft released on 8 February 2018 and includes supporting documents in relation to the heating and cooling load limits:

Overview: Key energy efficiency changes for residential buildings

Report: Principles and methodology for setting NCC heating and cooling load limits, developed by TIC and EES

E.1Consultation questions for the RIS

Comments on all aspects of the Consultation RIS: Inclusion of heating and cooling energy load limits into NatHERS assessments, SPR February 2018 are invited using the ABCB RIS response form available by clicking here by close of business Friday 13 April 2018. Comment can be emailed to [e-mail] with the subject title “Heating and Cooling Load limits”. Questions below have been developed to guide responses: