Replacing diesel boilers at New Zealand schools
Diesel boilers are being replaced at up to 70 schools nationwide, removing dependence on diesel for heating and protecting schools from future fuel price shocks.
The upgrade is expected to save around 600,000 litres of diesel per year, delivering cost relief while improving long‑term resilience.
Until diesel boilers are replaced, here are some ways to make their use more efficient.
- Check the boiler temperature – if it's currently set to 75–80°C, consider reducing it to around 65°C during milder weather.
- Make sure the radiator thermostat is correctly set:
- classrooms: set to 3 (approximately 20°C)
- hallways and circulation areas: set to 2.5 (approximately 18°C).
- Review how the areas heated by the diesel boiler are used after hours.
- Consider turning the boiler off earlier in the day once spaces have reached a comfortable temperature. Once a room reaches the target temperature, heating demand often reduces.
- Arrange a boiler service – and ensure the combustion settings are accurately tuned to maximise efficiency and minimise fuel use.
Planning for replacement of RNG boilers
Schools with boilers using reticulated natural gas (RNG) should be planning to replace their gas boiler in the next 10 years due to the decreasing supply of RNG.
Before progressing a boiler replacement, schools should seek appropriate technical advice to understand the condition of the existing system, the school’s heating demand, available infrastructure, and the most suitable replacement options. Please speak to your NZSPA Property Advisor for more information.
Alternative heating solutions
The most appropriate heating solution will depend on site-specific factors, including heating demand, existing infrastructure, electrical capacity, site constraints, fuel availability, operational requirements, and whole-of-life cost.
Common replacement options include:
- wood pellet boilers, which may suit schools with centralised heating systems and reliable access to pellet fuel
- wood chip boilers, which may suit larger sites with higher heating demand and sufficient space for fuel storage and delivery
- air-to-water heat pumps (hydronic heat pumps), which may suit sites with existing radiator or hydronic distribution systems
- air-to-air heat pumps or split systems, which may suit smaller schools, individual buildings, or sites where a centralised heating system is not practical
- Variable Refrigerant Flow (VRF) or Hybrid VRF systems, which may be suitable where schools require efficient heating and cooling across multiple spaces.
Other solutions may also be considered where appropriate, based on each school's requirements and technical advice. Replacement solutions should be selected based on whole-of-life cost, technical advice, and site assessment, rather than applying a standard solution across all schools.
You can find further guidance on heating and cooling solutions for school buildings on our Designing Quality Learning Spaces (DQLS) page.