Green buildings in New Zealand may not be as green as they seem, with difficulties in predicting energy and water efficiencies meaning what looks green on paper might not be so in practice, a researcher says.
The green building business is growing in New Zealand as companies try to either cut back on costs through water and energy efficiencies, or to give their brand a boost by being green.
At present, one of the only certification systems is the Green Star system, run by the New Zealand Green Building Council.
But an Auckland University PhD student has found that a proportion of certified “green buildings” may be misrepresented in the market.
If the problem was anything like it was in the US, up to a third of green buildings may not reach their advertised potential, Jeremy Gabe said.
This could result in tenants wanting to pay less for occupying a building they thought was greener than it was.
Mr Gabe, who has been involved in the US Green Building Council and came to New Zealand in 2004, has researched New Zealand buildings for five years.
He said the green building market in New Zealand was relatively small but growing rapidly.
“We are almost at a point where the owners of most new buildings have at least considered green design in their construction.”
The problem, Mr Gabe said, lay with the certification being handed out based on the design of the building and engineers’ tests, rather than how it actually performed when it was functioning with people in it.
“One key component of green building certification – potential operational energy efficiency – is difficult to predict before occupancy, but my research shows that only 15 per cent of buildings perform within the range of energy savings predicted.”
The problem was similar when predicting water efficiency.
“The major outcome of this is that there is still huge variability and therefore what seems to be green or has the potential to be green, you can’t really be confident that it meets your particular expectations of green.”
Mr Gabe said New Zealand building owners may soon be forced to meet standards introduced in Australia where the owners of any building more than 2000 square metres have to disclose the energy performance at the time of lease and sale.
However, Roman Jaques, a senior environmental building scientist with building industry research organisation Branz, said some of the research was “unnecessarily inflammatory as environmental building certification is a very new field in New Zealand and the issue of post-occupancy performance checking has been always recognised by Green Star while developing their existing rating tools”.
Mr Jacques conceded Mr Gabe made “many valid comments on the potential divide that can exist between the rated building performance and actual building performance, and his concerns resulting from this”.
He said the New Zealand Green Building Council was working on a building performance certification tool.
