How to Choose the Right Exhaust Fan

Exhaust fans are an essential part of any home where moisture, steam, or unpleasant odours can build up.

From dealing with fogged-up bathroom mirrors and lingering smells in the kitchen to keeping mould and mildew at bay, these hardworking appliances make a real difference.

But when it comes to choosing the right exhaust fan, what should you even look for?

Let’s look at all you need to know to choose the right wall or ceiling exhaust fan for the rooms in your home that will benefit most from its installation. Because when those rooms benefit, you and everyone in your house benefit.

Why Clean, Fresh Air Matters for Health

Clean, fresh air is more than a pleasant luxury; it’s a fundamental ingredient for healthy living.

The purpose of an efficient exhaust fan is to expel humid air packed with moisture, odours and microscopic nasties, usually from the bathroom, kitchen or toilet, before they settle on surfaces. A lack of sufficient ventilation allows warm steam from a shower or sizzling steak to turn into stubborn condensation.

This effectively creates the perfect environment for mould and mildew to thrive. Mould spores can irritate asthma, damage paintwork, and even rot timber over time.

By sending stale air outdoors and replacing it with cooler fresh air, ceiling exhaust fans keep bathrooms, kitchens, and toilets drier, safer, and infinitely more comfortable.

Good airflow also helps your air-conditioning work less. It helps to cut your energy bills while preserving healthy air indoors.

Numerous Exhaust Fan Types To Choose From

Choosing the right exhaust fan depends on numerous factors, including room size, moisture levels and the path available for stale air to escape. There is a range to choose from that includes:

• Wall or window fans – Perfect for ground-floor kitchens, these fans vent directly outdoors through a wall or window. They’re great at quickly removing smoke, odours and humid air.
• Ceiling exhaust fan – A simple stock model that sits flush in the ceiling and expels stale air into a well-ventilated roof space. It’s an ideal choice for bathrooms and toilets with typically short duct runs.
• Inline exhaust fan with ducting – Mounted above the ceiling and connected to a flue, the remote motor keeps noise down while maintaining strong airflow. It makes for a smart solution for ventilating through the roof.
• Combination heat-light-fan units – An energy-efficient option for compact bathrooms. They feature integrated lamps that warm the space, bright LEDs that add light, and a fan that clears steam before condensation or mould can take hold.

Choose and install a ceiling exhaust fan that best suits your room, and you’ll enjoy quiet ventilation, maximum efficiency and consistently fresh, healthy air throughout the home.

Calculating Exhaust Fan Capacity

Whichever fan option you choose, one factor you’ll need to consider is the exhaust fan capacity. This all comes down to how many times the air in the room needs to be replaced.

Exhaust fan capacity is measured in cubic metres per hour (m³/h) and depends on how many air changes per hour (ACH) your room requires. Under Australian Standard AS 1668.2, bathrooms and kitchens typically need 20 ACH, while toilets need about 10 ACH.

To calculate the right size fan:

1. Multiply the room’s length × width × height to get the total volume in cubic metres.
2. Multiply that number by the recommended air change rate.

Example: A 3m × 2m × 2m bathroom = 12m³.12m³ × 20 ACH = 240 m³/h minimum extraction rate.

Fans for toilets don’t need to be so powerful because you only need to change the air in the room around 10 times an hour.

Smart Controls for Maximum Efficiency

Once you’ve considered comfort and capacity factors, it’s also worth considering the level of convenience and efficiency your exhaust fan provides.

Smart controls turn an ordinary exhaust fan into a quiet powerhouse of maximum efficiency. Modern stock models now come with a raft of features including:

• humidity sensors
• motion detectors
• adjustable timers

These features will only run the fan when the room actually needs help.

Instead of spinning for hours, the unit measures moisture levels, kicks in automatically during a steamy shower, then shuts off when the air is dry. That precise airflow management saves watts, reduces wear, and keeps noise to a whisper.

Many controls can be retro-fitted, so you can upgrade an existing ceiling exhaust fan without changing the style or room size.

The end result? Healthier air, lower power bills, and a far longer fan life.

Keeping Your Ceiling Exhaust Fan Quiet

The higher the rate of airflow a fan has, the noisier it gets. For many homeowners, choosing a fan therefore becomes a balancing act between the need to vent stale air and their tolerance threshold for noise when showering or cooking.

The noise levels are sometimes described as sones, which is a measure of loudness. More sones generally means a louder fan. One sone is quiet and four sones are noisy.

The other, more familiar measure of loudness is decibels, which you will see called dBA.  As a guide, breathing is rated at 10 dBA and a normal speaking voice at 65 dBA. A fan rated at 35 dBA is therefore considered quiet.

Best Exhaust Fan Position

The best and most effective position for your fan is generally as close as possible to the source of the fumes you want to remove, such as directly above a shower.

That being said, it is often more convenient in a bathroom to locate a combination light, heat lamp and exhaust fan in the middle of the ceiling. That’s because that’s where the wiring is.

The thing to avoid is having the fan too close to a window. If the fan is close to an open window, it will draw air directly from the outside and leave the rest of the room unventilated.

Ideally, your fan should have the right extraction value, quietness and energy efficiency. If you then select the right type and put it in the best spot, you have the best exhaust fan for your circumstances.

Exhaust Fan Energy Efficiency

Although exhaust fans are generally low-power devices, it’s worth checking their wattage. Just like comparing light bulbs, the lower the wattage for the same airflow performance, the more efficient the fan. Over time, this small difference adds up on your power bills.

Breathe Easy with the Perfect Exhaust Fan

Choosing the right exhaust fan is all about matching airflow, noise level, energy efficiency, and fan type to the room’s needs. Whether you’re clearing out kitchen smoke, bathroom steam, or toilet odours, a ceiling exhaust fan with the right capacity and smart features can make all the difference.

Don’t overlook correct placement or the importance of meeting Australian Standards – it’s key to keeping your home dry, healthy, and comfortable. With the right exhaust fan in place, you’ll enjoy fresh air, less mould, and better daily ventilation. Breathe easier knowing your home is properly protected.

Please note: Thanks for reading our blog “How to Choose the Right Exhaust Fan”. This information is provided for advice purposes only. Regulations differ from state to state, so please consult your local authorities or an industry professional before proceeding with any work. See our Terms & Conditions here.