Goodman Property Trust NZ and IAG, the major tenant of a Christchurch commercial office property, have together achieved the first whole building 5 star NABERSNZ rating.

The property, at 14 Show Place in Addington, 2.5 kilometres south-west of the city centre, underwent significant refurbishment of 7000 square metres of office space across six floors over two adjoining buildings.

Goodman NZ was prompted to undertake the project due to a need for post-earthquake remediation works and the pending expiry of IAG’s lease.

The sustainability-focused upgrade aimed to reduce operational costs, reduce the buildings’ carbon footprint and create a healthier environment for staff, according to the New Zealand Green Building Council, which administers NABERSNZ in collaboration with the Energy Efficiency and Conservation Authority.

The initiatives included installing a variable refrigerant flow heating, ventilation and airconditioning system with heat recovery, and installing CO2 sensors, LED lighting, daylight harvesting and occupancy sensors.

During the course of the project, Goodman NZ sold the property through Colliers to a group of local investors for $33.2 million, representing a 7.8 per cent yield, in November 2015. However it remained involved with the upgrade project in conjunction with the new building managers, Maori Hill Property Limited.

“We are pleased to be first to gain a 5 star NABERSNZ whole building rating,” Goodman NZ portfolio manager Anna Lough said.

“Goodman undertook the project because we saw it as a great opportunity to work collaboratively with one of our largest office occupiers in NZ. We were able to refurbish and add value to our asset as well as retain a quality customer and secure them a long term lease.”

Tim Griffith, national property and administration manager at IAG NZ, said the project had shown the company that energy efficiency improvements could be made cost-effectively in existing buildings. The retrofitting of LED lighting, for example, resulted in up to 20 per cent savings in lighting energy use and has a two to three year payback, he said.

“Airconditioning is always the largest component of energy use in a building so it’s worth seeking specialist advice from engineers to ensure the correct equipment is installed and you receive the best energy efficient outcomes,” Mr Griffith said.

He said the company was seeing a 40 per cent reduction overall in building energy use, even though the workforce within the space had increased.

The NZGBC said it was the first time a NABERSNZ rating had been carried out both for the base buildings and the tenancy.

It is also the first NABERSNZ rating Goodman NZ has achieved for one of its properties, although it has developed a number of other buildings that have been awarded Green Star ratings.

It is also currently developing the VXV project in partnership with Fletchers Building at the entrance to Auckland’s Wynyard Quarter. The multiple commercial properties in the office park development will all aim to achieve Green Star ratings.

“We’ve found that the buildings with the best energy performance are those where tenant and owner work collaboratively. Congratulations to IAG and Goodman, who have proven that working together can achieve market leading results that benefit both parties.” Alex Cutler, outgoing chief executive of the NZGBC, said.

To date, about 13 NZ tenancies have achieved a NABERSNZ rating, an NZGBC spokeswoman said.

In the coming year, the organisation plans to focus primarily on tenants, she said, and it expects that number to grow substantially over the next 12 months.