5 Star Rating from May 2006

From 1 May 2006 the Building Code of Australia increased its current energy efficiency provisions from 4-star to 5-star for the majority of Australian states. Click here to view your state's regulation.

These amendments are incorporated to limit green house gas emissions. According to experts this limit in greenhouse gas emissions would halt the impact of climate change in the country which faced the driest autumn since 1923.

This increase in energy efficiency requirements (from 4 to 5 star) can be achieved by controlling the flow of energy (heat) in houses which is another quest for constructors and builders. An Energy Efficient House is one built to maintain consistent 26 degrees temperature throughout the year by minimal use of electrical resources (fans, coolers, air-conditioners, heaters etc). According to Building Code of Australia (BCA), such a house needs to cover 5 main areas:

Building fabric: Reflective materials and insulation levels in the roof, walls and floor depending on the climate control conduction of energy through the building fabric.
Solar radiation: external glazing for a house that prevents heat loss in winter and unwanted solar heat in summer.
Building sealing of doors, windows, roof lights, chimneys , flues , exhaust fans etc to control air leakage into or out of a building. This avoids an increased need for heating or cooling. So less energy is consumed and greenhouse gases are emitted.
Air movement : Natural ventilation through adequate internal and external openings in a house provide useful cooling thus using less energy for air conditioning.
Services: to avoid wasting energy in building services systems like insulation of water piping to central heating systems and storage hot water units, and insulation of ductwork associated with heating and air-condition systems.

So from May 1, 2006 all new homes and homes undergoing major renovation need to comply with the regulation thus making it mandatory that roofs, external walls and suspended floors achieve a minimum total thermal resistance. More attention is paid to window standards and areas such as sealing capacity, air movement, hot water services, mandatory external glazing.

As new regulations come into play greater efforts to minimize heat gains into the home are the key tasks for constructors, builders and assessors. This legislation can currently be satisfied using the NatHERS or Firstrate software, however AccuRate the second generation software of NatHERS after its successful trials (for over a year)has been released in mid April, it has ability to deal with more house designs and climate zones than FirstRate. Which would enable easy achievement of 5-star rating for Australian houses.