Energy equivalence ratings for houses, townhouses and units
The energy equivalence rating of a new dwelling is determined by the design of its building shell—the roof, walls, windows and floors. Dwellings that are designed to be more energy efficient are more comfortable to live in and can provide on-going savings to householders through reduced energy use for colling and heating.
New houses and townhouses, and major renovations to existing houses and townhouses (e.g. alterations and additions), must achieve a minimum 6-star energy equivalence rating.
New multi-unit residential buildings and major renovations to units must achieve an average 5-star energy equivalence rating. In September 2012, the government decided to maintain the 5-star energy equivalence rating for multi-unit residential buildings rather than adopt the national 6-star standard.
What the energy assessment delivers
An energy assessment takes into account the thermal performance of the building's shell (to provide internal comfort based on its design and climate. It predicts how much energy would be required to cool and heat the dwelling over the year.
The two most common assessment methods used to determine the energy equivalence of residential buildings for compliance are:
- software—using a software tool accredited under the Nationwide House Energy Rating Scheme (BERS Pro, AccuRate and FirstRate5), the assessment is undertaken by a house energy assessor who uses software to predict the design’s thermal performance. The software generates a star rating between 0 to 10 stars, with a 10-star building requiring minimal energy for artificial cooling and heating. A Universal Certificate will confirm the star rating of the building shell and also provides a summary of the dwelling's energy efficiency features.
- elemental—formerly 'deemed-to-satisfy' (DTS) provisions of the National Construction Code (previously known as the Building Code of Australia).
Other options are peer review (use of an expert) or the use of a reference building (comparison with a design that is known to comply).
Optional credits are available for photovoltaic (PV) solar energy systems (for houses and townhouses) and outdoor living areas (for houses, townhouses and units). The credits can be used towards compliance of the building’s energy rating.
An energy equivalence rating only deals with the thermal performance of the building. It does not include the energy use from fixtures and appliances, such as hot water systems, air conditioners, lighting and fridges.
The 6-star housing and 5-star multi-unit residential building requirements are regulated through the Queensland Development Code 4.1—Sustainable buildings.