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, experts 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 energy bills for residents.
About 40,000 new homes are built in Victoria each year, and all must adhere to 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 in reality,” Adam Selvay, Henley Homes energy and sustainability specialist, told The Sunday Age last week.
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, or global best practice comparisons or safety and health risk concerns raised by the visiting group, would engender any action or urgency from either the [Department of Climate Change and Energy Efficiency] or the [Australian Building Codes Board] at this time,” he wrote.
Mr Mahoney noted the attendees’ view that there is “overwhelming evidence” that the current star rating method “proves grossly inaccurate when constructed homes are performance tested”.
Bruce Rowse, from building efficiency consultants CarbonetiX, said air gaps are common around doors, light fixtures, window- and door-frames, and places where pipes or cables enter the home.
“Sealing is very important and to do it properly is really laborious. And there’s no inspection for it,” he said.
He also expressed concern that the regulatory regime doesn’t ensure insulation is adequately installed. “The building inspector has no idea of what insulation actually goes into the walls,” he said. “It’s also very difficult to validate exactly how well the ceiling is insulated.”
Victorian Building Commissioner Tony Arnel denied there was a systemic problem with air leakage standards or insulation in five-star homes. He maintained that an auditing process had consistently demonstrated that new homes complied with regulations.
“But building is not necessarily always a perfect science. We did some research two years ago with Air Barrier Technologies and that did tell us that there was potentially an issue with draughts and gaps that we needed to continue to work with industry to ensure that quality is met,” he said.
Mr Arnel said if testing proved a home did not meet its star rating due to building deficiencies, the owner could take legal action against the builder “because presumably it hasn’t been built to the right specification”.
Housing Industry Association building and environment director Kristin Brookfield said the association was not aware of any specific research on air leakage but acknowledged that a building’s energy efficiency is affected if it is not properly sealed.
“It’s important that this is seen as an issue about the rating tools,” she said. “This is not an issue about the actual construction of the homes.”
Lin Enright, from the Australian Competition and Consumer Commission, said that concerns had been raised with the Department of Climate Change about air infiltration, but no complaints or inquiries had been brought to the attention of the consumer watchdog.
The issue was privately championed last year by former Victorian Planning Minister, Justin Madden. In July, he wrote to the federal Minister for Innovation, Industry, Science and Research, Senator Kim Carr, requesting that the Australian Building Codes Board consider testing for air leakage to ensure greater energy efficiency of housing and other properties.