Ventilation

When an infected person breathes, speaks, coughs or sneezes, they may spread particles containing the virus.

Respiratory illnesses such as COVID-19, influenza and measles are mostly spreads by viral particles — small virus particles that can stay in the air for minutes to hours. Good ventilation helps remove virus particles in the air.

You can reduce the risk of spreading some illnesses by improving ventilation (the movement of fresh air in a close space).

Where possible stay home if you are sick and wear a face mask if you are in public places and shared spaces. 

Face masks (internal link)

It is important to keep the air in your room fresh. If you can, open windows on different sides of the room to help airflow.

To stop virus particles spreading within the home, reduce airflow from your room to other parts of your home:

• before opening the door into shared spaces, open your window for at least 5 minutes to freshen the air
• in a shared bathroom or toilet, close the door after you have been in the room and switch on the extractor fan, or open a window.

Monitoring CO₂ levels is one way to quickly assess whether a space is well ventilated when it is occupied. The level of CO₂ in a naturally ventilated indoor setting is used as a proxy to measure the adequacy of ventilation. When people breathe, they exhale CO₂, and the level of CO₂ in the room will increase. In a poorly ventilated room, CO₂ will remain in the room for longer, building up to higher levels. 

• A CO₂ reading below 800ppm indicates a well ventilated space.
• A CO₂  reading above 800ppm suggest that you may need to bring more fresh, outdoor air into the space.
• A CO₂  reading above 2000ppm, sustained for over 15 minutes would suggest a poorly ventilated space, with a much higher risk of spreading airborne infections.

If you have high CO₂ levels in your space or cannot measure CO₂ levels but are wanting to improve air quality there is a range of easy and practical steps you can take. 

We encourage you to let in fresh air every day, including during and after someone visits your home.

Try 1 or more of these ways to remove stale air.

• Open windows or doors on opposite sides of a room to help airflow.
• Open doors between rooms to ventilate hallways and spaces without windows.
• In kitchens, bathrooms, and toilets, switch on the extractor fan or open a window.
• Open higher windows wider than lower windows. This helps reduce draughts.
• If your windows do not open, check if your ventilation system filters (cleans) the air.

When leaving windows or doors open for periods of time, consider the safety of others — especially disabled people, children and pets.

Steamed-up windows can be a sign of low ventilation.

In cold or wet weather

Try 1 or more of these ways to refresh air without letting rooms get chilly or damp.

• Partly open a window for most of the day, for example, a 5cm opening.
• Fully open a window or door for 3 to 5 minutes every hour.
• Open a window whenever you leave the room, closing the door behind you.

You do not have to leave windows or doors open all the time.

In homes with heat pumps or ventilation systems

Heat pumps, air conditioners and ceiling fans do not introduce new fresh air. Instead, they move around air already in a room. You will need to open doors or windows to remove stale air and let in fresh air.

If you have a home ventilation system, check if it recycles air or filters air:

• If it recycles air, you need to open windows or doors to move stale air out and let in fresh air.
• If it filters or cleans air, this helps remove stale air and reduce the risk of virus particles spreading.

In rental properties

Landlords must provide good ventilation. If you live in or own a rental property, check ventilation rules on the Tenancy Services website.

Ventilation standard — Tenancy Services (external link)

Virus particles can build up quickly in crowded places such as buses or trains. It helps to sit or stand close to the door as airflow will be better.

Open a window on the bus if you can. Taxis and ride-share services often ask passengers to open windows.

We encourage you to wear a face mask in closed, crowded, and confined places such as public transport.

Face masks (internal link)