When a 6-Star energy assessment is conducted by an average energy assessor, the building is usually assessed against the main climate zone it is placed in. Here at Energy Rating Perth we go beyond the average assessment. If you consult with us prior to completing the building design, we can provide consultancy on many factors that will help improve your building’s thermal performance by taking the micro-climate your site is placed in into consideration.


Australia is primarily divided into 8 major climatic zones which is a generalization based on the overall effect of the mean temperatures, rainfall and relative humidity for certain areas. However, energy assessors here at Energy Rating Perth will further categorise the regions based on several factors like altitude, terrain, slope, vegetation, distance from the coast etc. Due to this geographical variation, we have a phenomenon called a micro-climate which may be alternate to the general climate of the area.  The following is a list of examples of micro-climate:

  • Rise in altitude means a drop in temp. Generally, for each 100 m rise, we can assume the temperature to be 0.7 degrees cooler.
  • Land-locked areas experience more severe climate and more sunshine.
  • Urban areas tend to have warmer nights due to the urban island heat effect
  • Hilly areas have more frequent wind occurrence and higher wind speed
  • Valleys have colder nights
  • Densely vegetates areas are cooler during the way and warmer at night as opposed to open plains.

It is unwise to base standard building design codes on the rules of the general climate for an area based on its geographical location in a climate zone. For instance, if you are based in a hot-arid climate zone, but your home is closer the coast, you will experience a high relative humidity and possibly lower temperatures as opposed to the inland areas of the same city. In this case, the building design should capitalise on sea breeze to ensure indoor thermal comfort as well as avoid using building materials that would be damaged due to the ocean salt sea spray. Similarly, in the Perth region, there is a significant temperature difference between the hilly region and the metropolitan area. Buildings designed and assessed in the hilly region should take this into consideration and prepare the building envelope accordingly.
If you are building a new home or would like to upgrade the thermal performance of your current home, consult one of our Energy Assessors at Energy Rating Perth for further information.