30 Day Returns
Best Prices, Best Service
If you see a better price let us try and beat it!
Excludes Remote Areas
Contact Us Sign In
Recently viewed ({{ items_count }})

Shopping for an Exhaust Fan? Here's How to Choose the Right One

Mitchell Elworthy

Exhaust Fan Size Calculator

Step 1: Select Installation Location

Step 2: Enter your room size

Enter your room width (m)

Enter your room length (m)

Enter your room height (m)

Your room size in m3

Result: Approximate Fan Capacity should be between:


Location Air Changes Per Hour
Bathroom (toilet only)   6 – 15
Bathroom with a shower  15-25
Bedroom 5-8
Cafe 15-25
Computer Room 6-10
Factory / Workshop 6-10
Garage 6-8
Commercial Kitchen 20-30
Domestic Kitchen 15-25
Laundry(No Dryer) 6-15
Laundry(With Dryer) 15-25
Commercial Laundry 11-20
Office 4-6
Roofspace 8-10
Sub Floor 6-10
Spa Bathroom 15-25

*Use this calculator as a general guide only

According to the Australian Government's Department of Agriculture, Water, and Environment, Australians spend 90 per cent of their days indoors. While Australia has not done extensive studies on the qualities of indoor air, recent studies by the EPA in the United States have put indoor air pollution in the top five list of risks for public health hazards. 

The air you breathe matters. When you're inside your home, you have some control over the quality of that air. Proper ventilation can reduce contaminants in your air and improve its quality. 

This is why exhaust fans exist. 

Keep reading to learn everything you need to know when choosing and installing an exhaust fan. 

Why Does Ventilation Matter?


Moving air is healthy air. To avoid contaminated air in your home, you need to keep it circulating from fresh air outside moving in to replace the unhealthy air inside. That moving air will keep you healthy. 

When you do not have proper ventilation, mould sickness and general illness will follow. Plus, your house smells stale and mouldy. 

The air you're breathing in your home can make you sick if you do not ventilate your home properly. 

How sick, you might ask? 

Indoor air pollution leads to a wide range of health problems, both in the short and long term. 

When you have poor indoor air quality, sickness, both acute and chronic, can result. Your eyes, nose, and throat will burn with irritation. Neurological responses like headaches and dizziness can result from poor indoor air quality as well. 

You may just feel unusually fatigued if you have indoor air pollution. If you find yourself with asthma-like symptoms, you may not have asthma but rather have indoor air pollution. Some people believe they constantly have a cold, but truthfully, they just have bad air quality in their homes. 

The fact that indoor air pollution causes asthma and cold symptoms makes diagnosing the problem difficult. 

If you're exposed to indoor air pollution for long periods, you can have even more serious effects. Individuals have reported heart problems, chronic respiratory illness, and even cancer as a result of poor air quality. 

The Good News: Ventilation Helps

There is good news in the midst of these thoughts about mould and illness: ventilation helps. 

Even just opening a window can make a difference in bringing fresh air in and letting unhealthy air out. Exhaust fans will speed up the ventilation process, pumping bad air out and circulating the air in your home. 

Exhaust fans also make your house smell better. They reduce mould spores and protect your walls and fixtures. 

You do not just have mould spores in your home. Your furniture and carpet also emit gasses. Other pollutants like pet dander and smoke from fireplaces pollute your indoor air.

A good exhaust fan keeps the air moving and protects your lungs and overall health. Bathroom and kitchen range hoods can pull the contaminated air outside. This makes your inside air even easier to breathe.  

How Does Ventilation Work? 

Damp buildings cause mould and other contaminated air issues. When a building is exposed to moisture, mould will grow. Constant heat and humidity on top of that exposure will feed the mould, allowing it to infest the structure. 

To keep your home from having a mould problem, you need to keep your relative humidity between 30 and 50 per cent. You can attempt to keep the mould and humidity at bay by using a dehumidifier. 

However, your best bet to keep your home healthy lies in using proper ventilation. This means an exhaust fan can become your best weapon in the fight against unhealthy indoor air. 

Exhaust fans are fans installed in key areas in your home. Typically, you can find an exhaust fan in humid rooms like bathrooms and kitchens.

The fans will work in reverse. They do not blow outside air into the house, but rather they suck the air out of the house, pulling out humidity and forcing the air to move and circulate in the house. 

Typically a technician will vent the exhaust fan so the inside air it pulls from the home will go outdoors. Sometimes an exhaust fan will pump air into the attic to keep it ventilated as well. Mould can grow anywhere, so you want to keep all of your tight spaces ventilated. 

The key to avoiding proper indoor pollution lies in having proper ventilation and in keeping you exhaust fans clean. If the fan begins to grow mould in it, then you're just circulating bad air. 

Proper ventilation keeps you indoor air clean. It reduces the irritating particles that can cause illness and reduce productivity.

Schools and offices have noticed an uptick in productivity when they reduce pollutants and focus on air quality. So ventilation helps you stay healthy and focused. 

What Type of Room Needs Ventilation? 

Any room with excess moisture needs an exhaust fan or increased ventilation. So bathrooms, laundry rooms, and kitchens all benefit since their showers, sinks, and dryers produce excess moisture. Without proper ventilation in these rooms, mould and mildew will begin to grow anywhere it can. 


Kitchens exhaust fans come in the form of range hoods. Typically, a homeowner will turn on the range hood when cooking something steamy or smokey. The range hood grabs the smoke, steam, or greasy air and then pulls it out of the house. 

If you have a large kitchen, you can get a larger kitchen exhaust fan that pulls outside air in to replace the air it sucks into the house. 


Even garages require ventilation. Even though contractors often build houses to seal them off from common living areas, gasses from the garage can still escape into the home. When you open the door to the garage, you cannot stop gasses from entering the home. 

Newer garages feature fans that kick in when a garage door moves. When the garage door opens to let a vehicle in the garage, the exhaust fan starts and runs for 20 minutes to remove the fumes the car brings into the garage. 

Work Rooms

If you have a workroom or a craft room, an exhaust fan makes sense. If you enjoy painting or staining, you will have excessive fumes in that room. Vent fans will remove contaminated air before it moves onto the rest of the house and affects others. 

Whole-Home Fans

If you live in a humid climate, a whole-house fan will serve you well. This exhaust fan does what all exhaust fans do: it sucks out indoor air and improves the overall quality of air in your home. 

You can combine a whole-house exhaust system into your HVAC, or you can just tie it in with other fans in the home such as in your kitchen or bathroom. 


Even the cleanest bathroom can smell. By their very nature, bathrooms attract bad human-centred odours. An exhaust fan will keep your bathroom free of humidity and those nauseating smells. 

You can install ceiling-mounted, wall-mounted, or inline fans in a bathroom. Ceiling-mounted, like their name implies, are mounted in the ceiling. They push air either into the attic or out through the roof. 

Ceiling-mounted fans will have the option of a 2-in-1 fan which doubles as a light and a fan or a 3-in-1 fan with a light, fan, and heater. The 3-in-1 fan will have a light, exhaust fan, and warming light, so when you flip the switch, you have both heat and circulation. 

A wall-mounted fan sits in the wall. A wall-exhaust fan pumps air through the outside wall of the house. Typically, people use a wall-mounted fan when there's no way to vent to the attic. 

An in-line fan also exists in the bathroom. You will find this type of fan in the ceiling or the wall.

The difference with the inline fan lies in its motor placement. Sitting between ducts, the inline fan motor pulls air outside. The motor is not attached to the ceiling. 

As a result, inline fans are some of the quietest fans on the market. They also work best when you do not have enough room in your ceiling.  

Window-mounted exhaust fans sit in the window of the bathroom. They work best when you do not have enough room or the ductwork for an exhaust fan.  

roof-mounted fan is installed in the ceiling of a room, but it extends above the roof. You can see a roof-mounted fan from the exterior of the home. Roof-mounted fans typically work to ventilate attics, keeping them free from humidity. 

How Big of a Fan Do I Need? 

The size of the fan you need depends on a few things. First, how big is the room where you need a fan? And second, how much air do you need to move? 

You can use a fan-size calculator to determine the approximate size of fan you ultimately need, keeping in mind that speed matters just as much as size. 

Size of Room

A bathroom fan needs to move air efficiently since it is sucking out a large quantity of humidity. Most people run their bathroom exhaust fan only when they shower or create a bunch of steam. 

Experts say your bathroom exhaust fan should change the air in the bathroom approximately eight times in one hour. 


Make sure you pick a fan that has a noise you can tolerate. Some fans are louder than others, so you need a fan that you can live with noise-wise. You'd hate to bring in a fan that helps eliminate air pollution but contributes to sound pollution in your home. 

When you go to the store to pick out a fan, ask if you can hear the fan on. What does it sound like? Do you have to raise your voice? 

Experts rank noise level in sones. A basic refrigerator puts out a sound of about one sone or less. Office noise typically rates around three sones. 

The type of fan and the room where you put that fan will affect the sound quality. For example, an inline fan typically is quieter because of its remote motor. Fans that rest on the wall or ceiling make more noise. 

The room that you put the fan in will change the sound of the fan as well. If you have an echoey room, to begin with, that has a high ceiling, the fan will sound even louder. 

In your bathroom, in particular, you want a fan of 1 sone or less. Some can get as low as 0.3 sones. 

What is Air Changes Per Hour? 

Air changes per hour refer to the amount of outside air you should have introduced into a room or building within an hour. Buildings in Australia have a rate between 1.4 and 39 air changes per hour. 

Essentially, this term refers to how well ventilated a room or a home is. The higher your ACH, the more ventilated a room is. 

Researchers in Australia state that many new Australian detached homes allow one air change per hour. This means the home naturally releases over 24 volumetric air changes a day. 

How to Install an Exhaust Fan

If you're an experienced weekend warrior of do-it-yourself projects, you can tackle installing an exhaust fan. Before you begin an exhaust fan installation project, though, consider a few things. 

You may have to run electrical wiring and ductwork through your attic. If you're replacing a fan, you will need to ensure the old wiring can handle the needs of the new fan. 

You should also check your building codes before you start tearing out ceiling or walls.  

Suck Out the Bad, Bring In the Good

A good exhaust fan will keep your home healthy. Stay focused and healthy by keeping your air moving. 

For all of your lighting and fan needs, contact us. We have a healthy inventory of everything you need to keep your home lit and ventilated. 

Current Discount Terms and Conditions

Australia Day Sale!




*Can not be used on previous order. Can not be combined with any other discounts. 

*Excluding brands:
 Big Ass Fans

Current Discount Terms and Conditions

Australia Day Sale!




*Can not be used on previous order. Can not be combined with any other discounts. 

*Excluding brands:
 Big Ass Fans