NSW Part H6 Energy efficiency
Introduction to this Part
This NSW Part H6 replaces Part H6.
This Part is intended to improve the efficient use of energy in building design and construction, as well as the energy usage by key equipment installed in a building.
From 1 May 2023 to 30 September 2023 NSW Parts 2.6 and 3.12 may apply instead of NSW Part H6 of NCC 2022 Volume Two. From 1 October 2023 NSW Part H6 of NCC 2022 Volume Two applies.
- Where a relevant development consent or an application for a complying development certificate requires compliance with a BASIX Single Dwelling or Multi Dwelling Certificate issued under Version 3.0 or earlier, NSW Addition NSW 2 Energy efficiency of NCC 2019 Volume Two Amendment 1 applies.
- Where a relevant development consent or an application for a complying development certificate requires compliance with a BASIX Single Dwelling or Multi Dwelling Certificate issued under Version 4.0 or later, NSW Part H6 of NCC 2022 Volume Two applies.
- Where a relevant development consent or an application for a complying development certificate requires compliance with a BASIX Alterations and Additions Certificate, NSW Additions NSW 2 Energy efficiency of NCC 2019 Volume Two Amendment 1 applies.
In NSW, Class 1 buildings and certain Class 10 buildings are subject to BASIX (the Building Sustainability Index).
BASIX is the web-based planning tool designed to assess the potential performance of certain residential buildings against a range of sustainability indices including thermal comfort and energy. Commitments made under BASIX become a condition of the relevant development consent or complying development certificate.
BASIX applies in NSW to all new Class 1 buildings, certain Class 10 buildings; and to alterations and additions to buildings of those classes where the work is subject to BASIX and also where an applicant elects to comply with BASIX.
The provisions of NSW Part H6 are therefore designed to complement requirements that arise under BASIX and which are implemented via the development consent.
Where BASIX is not applied to alterations and additions to these buildings, the provisions will also complement council development controls that require energy efficiency measures to be incorporated as part of the alterations and additions.
NSW H6P1 Building fabric2019: NSW P2.6.1(a)
- NSW H6P1 only applies to thermal insulation in a Class 1 or 10 building where a development consent specifies that the insulation is to be provided as part of the development.
- NSW H6P1(2) only applies to a metal framed roof and metal framed wall.
- In NSW, provision of thermal insulation of the building fabric may be nominated as a commitment on a BASIX (Building Sustainability Index) Certificate and form part of the conditions of development consent relating to the development.
- BASIX is applicable to alterations and additions the cost of which exceeds specified minimum values, or where an applicant elects to comply with BASIX. Where BASIX is not applicable, a council’s development controls may also specify the provision of thermal insulation in such alterations and additions.
- Thermal breaks between metal framing and cladding material of minimum thickness will reduce energy loss and contribute to the efficient thermal performance of the building.
NSW H6P2 Building sealing2019: NSW P2.6.1(b)
A building must have, to the degree necessary, a level of building sealing against air leakage to facilitate the efficient use of energy for artificial heating and cooling appropriate to—
- the function and use of the building; and
- the internal environment; and
- the geographic location of the building.
NSW H6P2 does not apply to—
- existing buildings being relocated; or
- Class 10a buildings—
- without a conditioned space; or
- for the accommodation of vehicles; or
- parts of buildings that cannot be fully enclosed; or
- a permanent building opening, in a space where a gas appliance is located, that is necessary for the safe operation of a gas appliance; or
- a building in climate zones 2 and 5 where the only means of air-conditioning is by using an evaporative cooler.
- The term “cannot be fully enclosed” means parts of buildings with permanent openings such as balconies, shade rooms, rooms with fixed louvres, mesh or other material that allows air flow. Adjustable louvres are considered to provide full enclosure to the opening they accommodate. Such rooms are unlikely to be conditioned given the high air flow rates; therefore application of the Performance Requirement to these parts of buildings would not result in reduction in energy use.
- Appropriate ventilation for gas appliances can be obtained from relevant legislation, referenced standards and product installation manuals.
NSW H6P3 Services2019: NSW P2.6.2
Domestic services, including any associated distribution system and components must, to the degree necessary, have features that facilitate the efficient use of energy appropriate to—
- the domestic service and its usage; and
- the geographic location of the building; and
- the location of the domestic service; and
- the energy source.
NSW H6P3 does not apply to existing services associated with existing buildings being relocated.
NSW H6V1 Application of NSW H6V32019: V2.6.1
The Verification Method in this Part only apply to—
- a Class 1 building; and
- an enclosed Class 10a building attached to a Class 1 building.
The Verification Method in this Part are intended to apply to whole Class 1 buildings and to whole Class 1 buildings that incorporate attached and enclosed Class 10a parts, such as attached garages. The Verification Method are not intended to apply to detached garages or to open carports.
NSW H6V2 Verification using a reference building2019: V18.104.22.168
This clause has deliberately been left blank.
H6V2 does not apply in NSW.
NSW H6V3 Verification of building envelope sealing2019: NSW V2.6.1
- a mechanical ventilation system must be provided that—
- can be manually overridden; and
- provides outdoor air, either—
- continuously; or
- intermittently, where the system has controls that enable operation for not less than 25 percent of each 4 hour segment; and
- provides a flow rate not less than that achieved with the following formula: , where—
- = the required air flow rate (L/s); and
- = the total floor area of the building (m²); and
- = the number of bedrooms in the building; and
- = the fraction of time within each 4 hour segment that the system is operational; and
- any space with a solid-fuel burning combustion appliance must be ventilated with permanent openings directly to outside with a free area of not less than half of the cross-sectional area of the appliance’s flue; and
- any space with a gas-fuelled combustion appliance must be ventilated in accordance with—
- clause 6.4 of AS/NZS 5601.1; and
- clause 6.4.5 of AS/NZS 5601.1.
The intent is that 10 m3/hr.m2 at 50 Pa is broadly equivalent to 10 air changes per hour at 50 Pa when applied to homes.