Bathroom Ventilation

Bathroom Ventilation at Mitre 10

Good bathroom ventilation removes steam, moisture and odours, which protects your walls, ceiling and cabinetry from mould and paint damage. The range includes exhaust fans, three-in-one heat-light-fan units and ducting accessories. Look at airflow in litres per second, noise rating and whether the fan ducts to outside (required) or only into the ceiling cavity. Installation requires a registered electrician.

What size bathroom fan do I need?

Bathroom exhaust fans are rated by airflow in litres per second. The Building Code requires at least 25 litres per second of continuous airflow or 50 litres per second intermittent airflow for a typical bathroom. For larger bathrooms or ensuites with a separate shower, size up to 60 or 80 litres per second. Check the noise rating (under 2 sones is quiet) before choosing.

Does my bathroom fan need to vent outside?

Yes. Under the New Zealand Building Code, bathroom exhaust fans must vent to the outside of the building, not into the ceiling cavity or roof space. Venting into the roof cavity dumps moist air where it condenses on roof timbers, causing rot and mould. Use insulated ducting and a wall or soffit vent for the outlet to prevent condensation inside the duct.