27% percent reduction in energy leads to NABERSNZ excellence
Argosy Property Limited has reached another performance milestone at the Citigroup Centre, 23 Customs Street East in Auckland, lifting its NABERSNZ base building energy rating from 4 to 5 stars.
This achievement highlights a strategic focus on energy efficiency and asset performance, especially considering the building's age and complexity.
Background
| Building owner: | Argosy |
| Address: | 23 Customs Street East, Auckland |
| Final rataing: | 5 star NABERSNZ Base Building |
| Floor area: | 8,065 |
| Energy intensity: | 74kWh/year/m2 |
The Citigroup Centre is a 14-storey, multi-tenanted office tower that includes ground-floor retail and hospitality spaces. Originally constructed in the late 1980s, it has recently undergone refurbishment. The office tower utilizes a variable air volume (VAV) air conditioning system, which provides high fresh air rates and is known for its substantial energy consumption.
Argosy’s commitment to NABERSNZ enabled them to begin measuring energy usage and focus on enhancing building efficiency while maintaining occupant comfort. Collaborating with HVAC contractor, Ideal Air, allowed them to address the primary energy consumer— air-conditioning—and optimise its efficiency while ensuring the comfort of all occupants.
Improving performance
The team installed advanced metering systems to monitor energy use, uncovering inefficiencies such as systems running outside scheduled hours. A 25kW rooftop solar array was also added, supplying 10–15% of the building’s base load.
“Solar provides a low carbon energy solution that makes good commercial sense and we’re seeing great payback periods. It’s pretty much a no-brainer,” says Jeremy Koh, the building’s Property Manager.
He says for many of their existing buildings the solar installation is expected to pay for itself in just seven years—based on energy savings alone.
Efforts to reduce energy consumption and add solar led to a 27% reduction in base building energy from the grid.
“It helps us reduce our carbon footprint and makes our building more attractive.”
Saatyesh Bhana, Head of Sustainability, says there’s a growing awareness and demand for NABERSNZ and this independent verification tool provides transparency. These independent ratings with third party verification will also provide valuers the tools for the new international valuation standards that consider sustainability in connection with building valuations.
“It helps people compare buildings and helps avoid concerns about greenwashing. You can’t just say your building is energy efficient—this rating tool shows how efficient it really is.”
For others considering NABERSNZ, Jeremy’s advice is clear: “Really understandhow your electrical reticulation works. Every building is different. And get someone with in-depth NABERSNZ knowledge involved early.”
Future-focused
Micky Sutinovski, the building’s Asset Manager, sees the 5 star NABERSNZ rating as part of a broader journey.
“I think it all comes down to proactive management. The 5 star rating is a great recognition of that effort—but it wasn’t the primary goal. We are focused on energy efficiency and tenant experience and the rating followed as a result.”
In saying that, Jeremy remains hopeful they can continue to improve performance
“We’re still a work in progress—hopefully we can get 5½ stars next time.”