Warm cool

It is a requirement for new Australian residential buildings to be designed and built to meet a minimum level of thermal performance.  

A House Energy Rating is a measure on a scale from 0 stars to 10 stars which corresponds to the average amount of energy required to keep the rooms in the dwelling at a comfortable temperature.  

  • A dwelling rating 0 stars requires a lot of energy to keep the rooms at a comfortable temperature
  • At the other end of the scale a rating of 10 stars requires next to none.

The minimum star requirement for new buildings is governed by the Australian NCC (National Construction Code)  

  • All states have 6 stars is the minimum requirement for new dwellings, apart from NSW
  • In NSW designs are assessed under BASIX.
    • BASIX allows a DIY method for achieving compliance with thermal performance requirements, or
    • a modelling approach similar to other states (but with less stringent requirements)

Energy Imaging are experienced at conducting Thermal Performance Assessments on your design and are accredited by ABSA (Association of Building Sustainability Assessors)

We use the modelling software 'FirstRate5' to assess your design.  This software is one of three software packages approved for use under the Nationwide House Energy Rating Scheme (NatHERS), and Energy Imaging offer the services of a trained and experienced accredited assessor.   

The modelling takes into account multiple factors which affect the building's thermal performance such as climatic zone, location, orientation on the block, room layout including window location and size, construction materials, and occupant behaviour.  These factors are covered in more detail on the NatHERS website.

Energy Imaging can:

  • conduct a House Energy Rating assessment on your design
  • recommend changes in design or materials to meet the minimum star rating
  • help you achieve a higher star rating than the minimum requirement - many people building a new home are interested in cost effectively decreasing their long-term energy consumption


Energy Imaging recommend the following as the best methods of reaching 6+ stars in home design.

  • Plan for north facing aspect with large windowed living areas on the north side
  • Couple the concrete slab to the ground
  • Put minimal window area on the south and west sides of the house
  • Incorporate thermal mass into the inside of the building envelope
  • Draft seal all possible intrusions into the building envelope - extraction fans, doors, windows and wall/floor and wall/ceiling joins
  • Insulate roofs and walls with insulation to suit climatic region
  • Select appropriate roof colour for your climate
  • Provide eaves/screens to allow solar access in Winter and shading in Summer
  • Avoid downlights and ceiling perforations
  • Use low emissivity glass on the south and west faces.
  • Double glaze using window frames with thermal breaks.