Heat pumps take off: One of New Zealand’s largest air-con systems goes electric

Auckland Airport has switched on a fleet of 11 industrial scale heat pumps in its international terminal – one of the largest installations of its kind in New Zealand – marking a major milestone in the airport’s plan to phase out natural gas and cut carbon emissions from its operations. 
 

The new electric system replaces one of the country’s largest gas-fired air conditioning plants, which has heated the 141,000m² international terminal for more than 50 years. Now that the system is operational, it is expected to cut natural gas use by around 40 per cent, while supporting comfortable journeys for the 30,000 travellers who pass through the terminal each day.  
 
Each unit - roughly the size of a shipping container – delivers up to 600kW of heating or cooling, around 100 times the output of a typical home unit. Together, the heat pumps provide efficient, low emissions climate control across the terminal, from check-in and departures through to airside dwell and biosecurity areas. 
 
Mary-Liz Tuck, Auckland Airport Chief Strategic Planning Officer, said the project involved retiring a 1970s power centre and craning the twelve-tonne heat pumps up to 30 metres into position on the terminal roof.  
 
“This project marks an important step in how we’re modernising the airport’s core infrastructure while materially reducing the emissions within our control. 
 
“Electric heat pumps allow us to move away from natural gas and make meaningful progress towards our goal of cutting Scope 1 and 2 emissions by 90% by 2030, compared to a 2019 baseline. 
 
“It’s a practical transition that improves the efficiency and resilience of the terminal today, while supporting the airport we’re building for the decades to come.”                                                                                                                                         
 
Transitioning in a live operational environment  
In FY25, natural gas made up 29% of Auckland Airport’s direct emissions, largely due to the energy required to heat the international terminal.  
 
Upgrading the system in a live terminal required the work to be carefully staged so flights continued as normal and passengers were not disrupted. The project involved replacing 50-year-old plant with new, energy-efficient Trane units imported from Asia. 
 
The installation also aligned with wider terminal integration works, including construction of the multistorey building connecting the international terminal with the future domestic jet terminal – which the heat pumps sit atop.  
 
Proven technology and future stages 
Martin Butcher, lead engineer on the project, said the heat pump technology was trialled over an 18-month period in 2023 in an adjacent section of the terminal before the full system was rolled out. 
 
“That testing gave us a clear picture of how the technology performs in a working airport environment,” said Mr Butcher.
 
The trial demonstrated how the system responds to Auckland’s fast-changing weather and fluctuating passenger volumes. 
“For the main system replacement, we transitioned the changeover in carefully planned stages, which allowed us to confirm how the system performed while keeping the terminal operating normally for travellers. This transition was undertaken over a five-week period.”
 
“The building effectively acts like a thermal buffer,” said Mr Butcher. “Temperatures shift slowly, which gives the system time to respond without creating noticeable temperature swings for people in the terminal.” 
 
Auckland’s mild climate supports efficiency. For much of the year, the outside air can be used for cooling rather than relying solely on mechanical systems, reducing overall energy demand while maintaining comfort.  
 
The heat pumps can run in mixed-mode - heating one area while cooling another – and reuse waste heat instead of discarding it, further improving efficiency during busy travel periods. 
 
The system began operating in September 2025, with fine-tuning over the next 6–12 months to balance comfort across fluctuating passenger volumes. Commissioning will continue through to next winter to validate year-round performance. 
 
Supporting the wider energy transition  
The heat pump upgrade is part of a broader programme to modernise Auckland Airport’s energy systems and support the wider transition to decarbonise Aotearoa. 
 
Emissions from Auckland Airport’s direct operations are a very small portion of those required to operate an international airport. The operation of aircraft contributes around 90% of Auckland Airport’s total emissions inventory but are a necessary part of connecting people and places. Addressing this emission source will take long-term coordination across the entire industry.  
 
“The decarbonisation pathway for the aviation sector is not straightforward with no single solution, but actions such as switching our terminal heating and cooling from gas to electric are steps we can take today,” Ms Tuck said.  
 
Auckland Airport is also investing in renewable energy generation to offset its energy usage and reduce its draw from the national grid. Rooftop solar arrays have been installed on the Transport Hub and Mānawa Bay, capable of generating 3.5MW of clean energy. 
 
These efforts contributed to Auckland Airport achieving Level 4 Airport Carbon Accreditation, placing it among the top airports globally for carbon management.  
 
“We take our carbon reduction target seriously and will continue to seek to use low-emissions solutions as we invest in our infrastructure,” said Ms Tuck.  
 
“These initiatives are part of building a stronger, cleaner, and more climate-resilient airport for generations to come.”