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

Overview: Heating and cooling load limits - NatHERS compliance pathway NCC 2019

The ABCB commissioned Strategy Policy Research to develop this Consultation Regulation Impact Statement (RIS), which accords with the requirements of Best Practice Regulation: A Guide for Ministerial Councils and National Standard Setting Bodies, as endorsed by the Council of Australian Governments in 2007. Its purpose is to inform interested parties and to assist the Australian Building Codes Board in its decision making on proposed amendments to the National Construction Code.

The Australian Building Codes Board

The Australian Building Codes Board (ABCB) is a joint initiative of all levels of government in Australia, together with the building industry. Its objective is to oversee issues relating to safety and health; amenity and accessibility, and sustainability in building. The ABCB promotes efficiency in the design, construction, performance and liveability of buildings through the National Construction Code (NCC), and the development of effective regulatory and non-regulatory approaches. The Board aims to establish effective and proportional codes, standards and regulatory systems that are consistent between States and Territories. For more information see the ABCB website (www.abcb.gov.au).

Consultation

This is a consultation document where interested parties are invited to provide comment on any matter raised in this RIS. A series of consultation questions have been provided, and respondents are encouraged to address these items to assist in the development of this document. Comments are invited using the ABCB RIS response form available from the Resource Library by close of business Friday 13 April 2018, and can be emailed to [e-mail] with the subject title “Heating and Cooling Load limits”.

The ABCB Office will review all comments received and incorporate stakeholder information and data into the regulatory analysis, as appropriate. The RIS will be revised in the light of stakeholder comments and will be forwarded to the Board as an input into its decision-making.
The Consultation RIS can be downloaded from the ABCB website.

Copyright

Copyright and licence notice

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Appendix AOverview

The purpose of this Section is to provide an overview of the proposed heating and cooling load limits for the Nationwide House Energy Rating Scheme (NatHERS) compliance pathway in the National Construction Code (NCC) 2019 Volumes One and Two. This section explains the need for heating and cooling load limits, how the load limits were developed, the outcomes and assumptions of the regulatory impact analysis for consultation. It also identifies a number of questions for feedback on the analysis. Responses to the questions at 5.1 will assist in the final decision Regulation Impact Statement.

A.1Why heating and cooling load limits are needed?

The NCC requires building designs to appropriately utilise solar radiation, as determined by local climates and geographic features. The current Performance Requirement states that:

“[A] building must have, to the degree necessary, a level of thermal performance to facilitate the efficient use of energy for artificial heating and cooling appropriate to—

…

(e) solar radiation being—

(i) utilised for heating; and

(ii) controlled to minimise energy for cooling…”¹

These mandatory provisions require solar radiation to be well utilised, such as through appropriate orientation for necessary solar heat gain during winter, or by minimising cooling needs by reducing the absorption of solar radiation through the building fabric in summer.

Rating of dwellings using house energy rating software, NatHERS, in NCC Volume One and Volume Two, is determined by the annual total energy load (i.e. a combined heating and cooling load). This may lead to a design that favours one side of energy use (either heating or cooling). A building can therefore meet the total energy load, but perform poorly in winter or summer.

There have been a number of research papers/articles showing concern about this approach. For example, in climate zones with both heating and cooling needs, the cooling energy need can be exacerbated by a dwelling design that favours winter performance².

Besides reducing energy use, introducing heating and cooling load limits may also result in health and social improvements. This includes decreasing peak energy load demand, lessening the pressure on the energy network, providing a more comfortable indoor environment year-round and assisting occupants (particularly those that are vulnerable) to cope with extreme weather.