Energ. Policy http://doi.org/h28 (2012)

Credit: © STOCKPHOTO/THINKSTOCK

Building performance standards — star ratings of energy efficiency — were introduced in Australia in 2003 and then toughened in 2006 and 2011. However, the steady increase in house sizes there has limited the potential for the standards to reduce greenhouse-gas emissions.

Stephen Clune of the Royal Melbourne Institute of Technology, Australia, and colleagues developed a residential emissions calculator to compare heating and cooling loads — the amount of heat that needs to be provided to (or removed from) a building in a given time unit, to maintain a comfortable temperature for its occupants — for 72 new Australian houses based on star ratings, house sizes by state, and international house sizes. They found that the impact of building standards on greenhouse-gas emissions depends significantly on house size. Their results estimate that, in the state of Victoria, the move of building standards from 5 to 6 stars in 2011 may be 38% less effective than expected, due to the recent increase in house size. Projections show that the state of Victoria will dominate new house emissions, even with further strengthening of the codes.