Healthy Homes Ventilation Requirements NZ: Windows and Extractor Fans
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Every habitable room in an NZ rental needs an opening to the outside that can be fixed open, with a total openable area of at least 5% of that room's floor area; kitchens and bathrooms also need qualifying extraction to the outdoors unless a valid alternative or exemption applies.
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Ventilation has two separate tests. Living rooms, dining rooms, kitchens and bedrooms need enough openable window, door, or skylight area. Kitchens and rooms with a bath or shower also need mechanical extraction to the outdoors.
Measure and verify
- Measure each habitable room's floor area and the net area that can actually open outdoors.
- Confirm the opening can remain fixed open.
- Check every cooktop, bath, and shower room for an extractor that vents outside, not into a ceiling cavity or through a recirculating hood.
- For fans installed after 1 July 2019, retain duct diameter or flow-rate evidence. Tenancy Services specifies 150 mm or 50 litres per second for kitchens and 120 mm or 25 litres per second for bathrooms.
- Record how any continuous mechanical system or exemption satisfies the detailed rule.
Older fans can qualify when they vent outdoors and remain in good working order, but a failed replacement must meet the current requirements. Keep installer specifications and photographs of the external outlet.
Primary source: Tenancy Services ventilation standard, reviewed 6 September 2026. See the full property checklist for the other standards.
Written from my own experience running rentals in New Zealand. It is general information to help you understand your options, not legal, tax, or financial advice, and RentManager is not your lawyer or accountant. Rules change and every tenancy is different - check your own situation with Tenancy Services, the IRD, or a professional before you act on it.