Bathroom and laundry ventilation — ceiling and wall-mounted exhaust fans in round and square formats, including high-extraction and low-profile models.
Sizing an exhaust fan
How do I size a bathroom exhaust fan?
Size on air volume, not floor area. Work out the room volume in cubic metres and aim to change the air roughly ten times an hour — a 3m × 2m room with a 2.4m ceiling is about 14m³, so around 140m³/hr. An undersized fan will run for an hour and still leave the mirror fogged.
Does an exhaust fan have to be ducted outside?
It should be. A fan that dumps into the roof space is just moving the moisture somewhere it will do more damage — that is how you end up with mould in the ceiling and rusted roofing screws. Run 150mm or 200mm duct to an external vent, keeping the run short and the bends gentle.
What is a run-on timer and do I want one?
It keeps the fan running for a set period after the light is switched off, usually adjustable somewhere between 5 and 30 minutes. It is the single most useful feature on an exhaust fan, because most of the moisture is still in the room when you walk out.
How do I stop the fan being so loud?
Compare the dB(A) figure on the product page and buy larger than you need — a quiet unit sits around 35dB(A) where a cheap one is closer to 50. A bigger fan on a lower speed shifts the same air far more quietly than a small fan at full noise, and rigid duct with gentle bends beats crushed flexible duct by a wide margin.
