20 June 2013 — South Australia had the highest average NABERS ratings in the country, according to recently released Commercial Building Disclosure statistics. NSW came out second, trumping rival Victoria, which was below the national average of three stars.

Under the Commercial Building Disclosure program, energy efficiency information is required to be provided to the government when commercial office space of 2000 square metres or more is offered for sale or lease.

Statistics from the first full year of Commercial Building Disclosure show that buildings are making a concerted effort to boost their NABERS ratings, though most of the market suffers from poor lighting efficiency.

The national mean NABERS rating of buildings covered by the legislation was three stars. Of the 874 buildings liable to report, most had a 4-star rating, but the average was dragged down by 98 energy-inefficient buildings with 0-star ratings.

When NABERS was graphed against net lettable area, the most common rating was 4.5 stars, reflecting the fact that larger buildings generally have higher NABERS ratings.

Mean NABERS energy ratings per state saw South Australia out in front with an average NABERS rating of 3.57. NSW was next with a rating 3.23 ahead of Victoria, whose average was below the national average on 2.85.

Director of WT Sustainability Stephen Hennessy told The Fifth Estate that CBD was driving buildings to perform better.

“When Commercial Building Disclosure started the mean NABERS rating was 2.5, so there’s a real push to increase performance thanks to the legislation,” he said.

He said that the number of ratings had “more than doubled” since becoming mandatory.

The big end of town was able to get their house in order long before mandatory disclosure, he said, but buildings that didn’t care to improve previously or did not have the resources to do so now had to declare poor performance, “warts and all”.

Hennessy said there was a risk for some tenants being associated with poor-performing buildings, including government clients, large companies with corporate social responsibility requirements, and those with sustainability interests.

Lighting was singled out as being particularly poor, and another risk for tenants.

The tenancy lighting assessment looked at the nominal lighting power density, a measure of lighting efficiency. Close to 36 per cent of NLA was rated “poor”, with more than 15 watts per square metre needed to light areas.

“From a tenant’s point of view this is a powerful bit of information,” said Hennessy. “It’s an area of the building tenants cannot control, so having efficient lighting is critical.”

“In my office, we have lighting that illuminates to 320 lux. Our lighting load is 5.8 watts per square metre. Some buildings have offices where lighting is meeting the standard but using four times the energy.”

He said tenants would not want to be locked into using three to four times the energy for lighting as others, and that CBD was a good tool for prospective tenants to compare leasing options.

See the full statistics here.