Hundreds of thousands of new homes across the country are not performing at their promised energy efficiency rating, forcing residents to use up to double the predicted energy required for heating and cooling, industry officials say.
Research by air-tightness testing company Air Barrier Technologies has shown that air leakage in new homes is five to 10 times worse than expected under the star-rating scheme.
This means that an average five-star home is likely to perform only to a three-star level, potentially doubling expected energy bills for residents.
The Victorian Building Commissioner says builders who deliver homes that have not been properly sealed or insulated to meet the set star rating could be sued by buyers.
About 40,000 homes are built in Victoria each year. All must meet the five-star standard. This will rise to six stars from May.
But a group of industry players, including Henley Homes, who have been lobbying state and federal government and building regulators to crack down on the air leakage problem, say unless more action is taken, customers cannot be confident their homes meet the stated star rating.
”At the moment there’s an assumption that houses are built to a far tighter standard than what we believe they are,” Adam Selvay, Henley Homes energy and sustainability specialist, said.
The question of builder liability was raised in a meeting with the Federal Department of Climate Change and Energy Efficiency and the Australian Building Codes Board in April last year.
Following that meeting, Terry Mahoney, president of the Air Infiltration and Ventilation Association of Australia, emailed other attendees, as well as federal government ministers and senior public servants, criticising officials for failing to respond to the issues discussed.
”It became apparent that no amount of scientific evidence, poor global best practice comparisons or safety and health risk concerns raised by the visiting group, would engender any action or urgency, ” he wrote.
He noted the attendees’ view that there is ”overwhelming evidence” that the current star rating method ”proves grossly inaccurate when constructed homes are performance tested”.
Housing Industry Association building and environment director Kristin Brookfield said the association was not aware of specific research on air leakage, but said energy efficiency was affected by poor sealing.
Bruce Rowse, of building efficiency consultants CarbonetiX, called for inspections to include checks on sealing and insulation installation.
Victorian Building Commissioner Tony Arnel said an auditing process had consistently demonstrated that new homes complied with regulations but admitted that research had shown more work needed to be done with the industry on ”draughts and gaps”.
