Factors that influence Star Ratings

Factors that influence an Energy Star Rating



Lot orientation determines how much sun can enter the home at different parts of the year

Good orientation will also allow:

  • Good solar access in winter time
  • Allow living areas to be placed on the north
  • Allow access to cooling breezes


The location or climate zone of the proposed house will influence:

  • Weather patterns the house will be exposed to
  • Amount of  shading required
  • What is considered a comfortable temperature


  • The amount of glazing and more importantly the orientation of the glazing is highly important.
  • Glass allows heat in 2 ways – through direct sunlight and through heat transfer through the glass.
  • Shading prevents heat from sunlight but not heat transfer.
  • Heat transfer is also detrimental to maintaining warmth in winter


  • Correct shading should allow winter sun to infiltrate the house while blocking out summer sun
  • Rule of thumb – eaves width should be 45% of window height
  • Alfrescos and verandahs on the north side should try to be avoided in the metropolitan area


For more information on how  Factors that influence Star Ratings will affect the energy efficiency of your house, or you would like to know more about the service Sustainability WA provide including an Energy Rating or Energy Efficiency certification for your project please contact us here or phone 08 9537 2000

Other terms sometimes used to describe an energy rating includes:  Energy Star, Energy Audit, Energy Ratings, Energy Efficiency Certificate, Energy Assessment, HERS, BER or EPC.

Sustainability WA can help you with them all!

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