ENERGY RATING OF RESIDENTIAL BUILDINGS

All residential buildings in Western Australia must comply with the Energy Efficiency Measures (EEM) of the Building Code of Australia (BCA). Energy performance must be demonstrated when obtaining development approval, as well as when applying for building approval.

The provisions applies to:

  • New Class 1 buildings (single houses)
  • New Class 10 buildings (non habitable) with a conditioned space
  • Certain additions and extensions

    APPLICATION OF THE PROVISIONS
    There are two options for assessing applications for compliance with the BCA energy efficiency provisions:

    1. A completed Energy Efficiency Check Sheet for approved solutions
      (Application of Part 3.12(a) Performance Requirement P2.6.1 for the thermal performance of the building is satisfied by complying with— (i) for the building fabric, Part 3.12.1; and (ii) for external glazing and shading, Part 3.12.2; and (iii) for building sealing, Part 3.12.3; and (iv) for air movement)
      or
    2. Certification from a registered software provider that the design complies
      (V2.6.2.1 Verification using stated value(a) A building must have an annual energy load, determined using a thermal calculation method, which is equal to or less than— (i) in climate zones 1 to 3— (A) the annual energy load equivalent to a 3.5 star house energy rating determined in accordance with the ABCB Protocol for House Energy Rating Software; or (B) the annual energy load value listed in Table V2.6.1 for— (aa) the location where the building is to be constructed; or (bb) the nearest location with similar climatic conditions, if the location is not listed in Table V2.6.1; and (ii) in climate zones 4 to 8, the annual energy load equivalent to a 4 star house energy rating. (b) In climate zones 1 to 3, the maximum annual energy load value may be increased by 20 MJ/m2.annum if— (i) a solar hot water supply system having a minimum of 2 solar collectors and a storage capacity of not less than 270 litres is installed to serve the building; or (ii) a gas or electric heat pump)

    Three programs are used for star-rating homes:

    • AccuRate (version 1.0)
    • BERS Professional - granted provisional accreditation 8 November 2007
    • FirstRate 5 - granted provisional accreditation 31 August 2007

    The Star Rating is a simulation that allocates a value between one and five stars to a building, with five stars being the most efficient (this is called the Building Energy Rating).

    A Star Rating of a building demonstrates the expected thermal performance within a specific climate type. It takes into account typical user occupant behaviour patterns and heat energy inputs into the house from appliance (water heaters, stoves, televisions etc.).

    Where a building may be both heated and cooled, the rating reflects the sum of the heating and cooling energy required to maintain the building within a comfort temperature band. In warmer regions (two thirds of Australia) where there is little heating or cooling used, the Star Rating reflects the amount of time that a building maintains a temperature outside of the thermal comfort band.

    Karl Boeing