Much of the regulatory drive to make buildings more energy efficient is misguided, according to a widely critical draft report from the Productivity Commission.
The NSW Building Sustainability Index (BASIX) and the Nationwide House Energy Rating Scheme (NatHERS) are unproven and further measures should be put on hold until they are properly evaluated, the commission says.
Measures which should be deferred would include new rules for apartment buildings to apply from next month, a minimum five-star energy rating for all new houses in all climate zones to apply from next May, and the extension of energy efficiency rules to commercial buildings and major renovations.
At the state level is the application of the BASIX energy conservation formula to new dwellings from July and to alterations and additions from October.
The report questions just about every aspect of current policy and conventional wisdom on energy efficiency and is sure to be roundly attacked by the conservation lobby.
It specifically targets local and state governments for introducing more stringent energy-saving targets than national standards. The case for such variations, which increase building costs, appears weak, it says.
The Australian Local Government Association has responded that "national productivity is enhanced by encouraging local innovation, not snuffing it out".
The commission has recommended a comprehensive and independent evaluation of existing requirements for building energy efficiency ratings and standards before governments introduce more stringent and widespread requirements.
Among its other controversial findings are:
■The Australian Building Codes Board should examine ways to reduce the scope for local governments to erode the uniformity of minimum energy efficiency standards for new houses.
■Before the states mandate energy-performance ratings for existing dwellings at the time of sale or lease, the Ministerial Council on Energy should commission an independent evaluation of the ACT rating scheme that has operated since 1999.
■Energy efficiency standards for residential buildings are based on computer simulation models that exclude many of the determinants of a building's actual energy efficiency and "star" ratings may be very different to actual energy consumption or efficiency.
■A national energy efficiency target is a poorly focused policy instrument that would be very difficult and costly to implement. It cannot be justified on the grounds of privately cost-effective energy efficiency and it has serious disadvantages as a way to address greenhouse gases.
The Commission said that computer software packages such as NatHERS and FirstRate which are used to measure the environmental efficiency of new buildings may not be an accurate indicator of actual energy efficiency. They may also be measuring the wrong things in that they do not measure energy consumption but "energy loads". These do not account for appliance efficiency, householder behaviour, climate variations and other factors.
"Building standards may have little impact on actual energy efficiency compared to, say, a policy that changes householder behaviour," the report concludes.
The commission heard expert evidence that six houses that had won awards from the Royal Australian Institute of Architects and been built before mandatory energy standards had been tested using computer simulation and for actual energy consumption. All were found to have below-average energy consumption but rated only zero or one stars on the computer. None of the houses could be legally built today.
"The case study evidence suggests that building energy efficiency standards could distort the housing market in favour of designs that rate highly using available energy-rating software, rather than on the basis of actual energy efficiency. In addition, innovation could be stifled in energy-efficient designs that do not fit within the paradigms used for energy-rating software," the report said.