Best Exhaust Fans for Adelaide Bathrooms: CFM Guide
A properly sized exhaust fan is the single most effective weapon against bathroom mould. But most Adelaide homes have fans that are undersized, poorly ducted, or not ducted externally at all. Here’s how to get it right.
How to Size Your Exhaust Fan
Australian Standard AS 1668.2 recommends a minimum of 25 litres per second (L/s) — approximately 50 CFM — for a standard bathroom. For ensuites or bathrooms without windows, increase to 40 L/s (80 CFM).
Ducting Matters More Than the Fan
A powerful fan ducted into the roof cavity just moves moisture from your bathroom into your roof space — creating mould there instead. The duct MUST go to an external wall or roof vent. Use rigid ducting (not flex) for maximum airflow.
Common Adelaide Mistakes
- Fan ducted into roof cavity (creates roof mould)
- Fan too small for the room (decorative, not functional)
- Fan only runs while light is on (needs a run-on timer for 15 minutes)
- Flexible duct kinked or compressed (reduces airflow 50%+)
Recommended Setup
Inline centrifugal fan (150mm), rigid ducting to external vent, run-on timer (15-20 minutes after light off), humidity sensor switch (runs automatically above 65% RH). Total cost installed: $400-$800.
For existing mould that a fan upgrade won’t fix, professional assessment ensures the moisture source is fully addressed. Get your free quote.
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