Software glitch undermines green houses

THE efficiency of Australian homes built to cut greenhouse emissions is in question due to errors in software that performs the calculations.

THE efficiency of Australian homes built to cut greenhouse emissions is in question due to errors in software that performs the calculations.

The errors, which are known to the CSIRO and the Department of Climate Change and Energy Efficiency, make it likely that builders, designers and those looking to build a house are making wrong decisions, a leading scientist in energy efficiency told The Australian.

The software tool designed by the CSIRO produces consistently false results and distorts the energy ratings of homes. This pattern over several years must be costing the building industry and home owners dearly, according to Terry Williamson, who discovered the errors and alerted the CSIRO this month.

Associate Professor Williamson said the waste would be "a debacle to rival the Green Loan scheme", another botched energy-efficiency initiative, if the impact of the errors were shown to be as significant as he suspected.

The news came as Julia Gillard announced tax breaks for business to improve the energy efficiency of their commercial buildings.

From July 1, businesses undertaking capital works to improve the energy efficiency of existing buildings -- from two stars to four stars or higher -- would be able to claim a one-off tax bonus of 50 per cent of the cost of the eligible assets. The tax break would enable a company spending $1 million to claim a $500,000 deduction, reducing its tax bill by $145,000.

CSIRO scientist Zhengdong Chen confirmed the errors in new homes caused by the software and said they were being investigated by the CSIRO along with the Department of Climate Change and Energy Efficiency, which manages the software. "We are in discussions with the department and we are looking at it to see how we can deal with it," Dr Chen said. "We do not know at this moment what the extent of the effect is."

A government spokesman said the Department of Climate Change and Energy Efficiency was aware of the issue but the "ratings for the majority of new homes are not affected, and at this stage it is premature to say there is any significant impact on overall house ratings or compliance costs".

The software being investigated is the integral tool in the Nationwide House Energy Rating Scheme (NatHERS), which is meant to satisfy energy-efficiency regulatory compliance for residential buildings under the Building Code of Australia. Decisions about materials and components for building construction are influenced by the Building Code, which relies on the software to determine energy efficiency.

Professor Williamson said the issue posed serious financial consequences as the combined cost of building homes to the energy efficiency required by the software was more than $6 billion a year. He said Energy Efficiency Minister Penny Wong and the Gillard government should withdraw the software from use pending further investigation.

"There should be an independent inquiry and a full examination of the software and the administration of it," Professor Williamson said. "Sections of the building industry together with the wider material and component manufacturers live or die depending on the Building Code requirements developed with the use of this software."

Holger Willrath, principal of the firm Solar Logic which has developed software used with the NatHERS tool, doubted any errors were as significant as described by Professor Williamson.

"The building industry would come to a halt if you suddenly pulled this software because buildings would not be able to get through the (compliance) process without it," Dr Willrath said.