Ventilation in schools

Ventilation in schools

In New Zealand, we have great outdoor air quality. The Ministry’s approach to indoor air quality and ventilation is centred around this and encourages behaviours that promote good ventilation. Our advice to schools continues to be maximise ventilation capabilities as much as possible while maintaining comfortable indoor temperatures to help to reduce the risk of transmission of airborne illnesses, such as COVID-19. 

The importance of ventilation

All New Zealand schools are designed to be well-ventilated, either naturally or mechanically. When airborne illnesses are prevalent, maintaining good indoor air quality reduces the risk of airborne transmission by regularly refreshing the air in a space. 

The COVID-19 pandemic will continue to require a health and safety response from schools to minimise the risk of transmission. As part of this, we’re continuing to support schools to maintain good ventilation in their spaces year-round. 

The best way to achieve good ventilation is to open windows and doors, either fully or partially, whenever you can. The exception to this is spaces that are fitted with ducted air conditioning systems (excluding heat pumps), which do not rely on opening windows to bring in fresh air.  

Our guidance is provided to help schools understand ventilation requirements and to assess and mitigate any risks caused by poor ventilation. 

Schools are encouraged to follow our guidance and fine-tune their ventilation strategies year-round, depending on the season and outdoor conditions.

Advice and guidance for colder weather

When it is colder outside, good ventilation practices need to be balanced with keeping rooms at a comfortable temperature. 

Airflow works better when its colder outside, and it is possible to maintain good ventilation with windows only partially open. Our advice to schools is to open windows for as long as practically possible, and to balance this with ensuring that the temperature remains comfortable inside. Windows that are ajar or partially open still promote good ventilation – every little bit helps. 

There are three key actions to improve natural ventilation during colder weather:

  • Heat: Heat the room before the start of the school day, which will allow people to open windows earlier in the day. Keep heating on throughout the day to stay warm, with windows partially opened whenever possible.
  • Open: Open windows by at least a crack or as much as you can while staying warm. Opening lots of windows a little can be more effective in colder weather. If the weather is bad outside, close what you need to stay comfortable. 
  • Reboot: Take refresh breaks to clear the air at different times during the day by fully opening all the windows and doors, preferably while having everyone exit the room. Aim to do this at least four times each day. 

More resources are available that provide additional advice on how to balance good ventilation with thermal comfort.

Support for schools

Support is available to schools who are concerned about maintaining good ventilation. This includes:

  • Guidance and resources available for download or print
  • Funding of urgent property improvements over $5,000 that are required to achieve good ventilation.
  • Distributing additional portable CO2 monitors and air cleaners at no cost to schools, to support them with good ventilation.
  • The ability to purchase suitable portable air cleaners and CO2 monitors from the Ministry’s nominated suppliers at discounted pricing.

For ventilation advice and to access this support, please contact your Property Advisor or our team on