Rental homes must have openable windows in the living room, dining room, kitchen and bedrooms. Kitchens and bathrooms must have extractor fans or an acceptable continuous mechanical ventilation system.

Mould and dampness caused by poor ventilation is harmful for tenants’ health as well as landlords’ property. The ventilation standard targets mould and dampness in rental homes.

Mould and dampness

To find out when your property needs to comply with the healthy homes standards use the compliance timeframes decision tool.

Compliance timeframes decision tool

Landlords that don’t meet their obligations under the healthy homes standards are in breach of the Residential Tenancies Act 1986. They may be liable for exemplary damages of up to $7,200.

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What is the ventilation standard?

All habitable rooms in a rental property must have at least one window, door or skylight which opens to the outside and can be fixed in the open position.

In each room, the size of the openable windows, doors and skylights together must be at least 5% of the floor area of that room.

Each window door, window or skylight must be openable and must be able to remain fixed in an open position.

All kitchens and bathrooms must either have an extractor fan that vents air to the outside or a continuous mechanical ventilation that meets certain criteria.

Extractor fans

If you plan to meet the standard with extractor fans they must meet the following criteria:

  • Kitchens – In any room with a cooktop, new fans or rangehoods installed after 1 July 2019 must have a minimum diameter (including ducting) of 150mm or an exhaust capacity of at least 50 litres per second.
  • Bathrooms – In any room with a shower or bath, new fans installed after 1 July 2019 must have a minimum diameter (including ducting) of 120mm or an exhaust capacity of at least 25 litres per second.

Landlords should ask installers for the details of the fan diameters, ducting and flowrate in writing, so they can show they are compliant with the healthy homes ventilation standard.

Use our online tool to find out if you need to install new extractor fans in the kitchen and bathroom of your rental property.

Ventilation tool

Continuous mechanical ventilation systems

The ventilation standard allows properties with certain continuous mechanical ventilation in kitchens and bathrooms to meet the standard. This is an alternative to meeting the standard by having extractor fans.

If your home was built with a continuous mechanical ventilation system, to meet the standard it must:

  • be designed to vent extracted air continuously from the property to the outdoors, and for a kitchen or bathroom, extracts the air directly from the room, and
  • have been installed in the property or a tenancy building that first received building consent on or after 1 November 2019 and was part of that original building consent, and continues to meet the requirements of the building consent.

Alternatively, if your home has been renovated and now includes a continuous mechanical ventilation system, to meet the standard, the system must:

  • be designed to provide ventilation for multiple rooms and to continuously extract air to the outdoors, and
  • extract air directly out of the kitchen and bathroom, with an exhaust capacity of at least 12 ℓ/s in the kitchen and 10 ℓ/s. in the bathroom. The actual flow rate may be varied (manually or automatically), in response to the demand for ventilation.

Recirculating systems (products like HRV and DVS systems), or fans that do not extract to the outdoors are not suitable to meet the ventilation standard.

Our guidance document has more specific information on the ventilation standard:

Ventilation guidance document. [PDF, 1.8 MB]

If you have an existing fan

Fans put in before 1 July 2019 must ventilate to the outside of the house and be in good working order, but they don’t have to meet the requirements listed above.

When they stop working, they must be repaired to be in good working order or replaced with fans which do meet all the requirements.

Exemptions to the ventilation standard

There are 2 specific exemptions for the ventilation standard. The information here is an overview. (external link)

Subpart 4 of the Healthy Homes Standards Regulations has further information on these exemptions(external link) — New Zealand Legislation

  1. A room doesn’t need to meet the requirements for openable windows and external doors if it was lawful when it was built or converted into a habitable space. If having fewer windows or doors was only lawful because the room met alternative ventilation requirements, then the room must still meet those requirements to qualify for this exemption. 
  2. This exemption applies to kitchens or bathrooms where it is not reasonably practicable to install an extractor fan. This exemption has a number of criteria which must all be met. We recommend landlords get professional advice and keep a copy of that advice to qualify for this exemption.

These 2 exemptions are in addition to the general exemptions.

General exemptions to the healthy homes standards

Further information

The ventilation standard is one of 5 healthy homes standards. Find out about the other healthy homes standards:

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