When you’re in the home design and renovation phase, bathrooms often raise more questions than answers—especially around ventilation, privacy, and compliance with building codes.
So, do bathrooms need windows?
While the answer isn’t always a straightforward ‘yes’ or ‘no’, it’s essential to understand the role of bathroom windows, when they’re legally required, and the advantages they offer in terms of health, comfort, and functionality.
We will discuss the importance of ventilation in bathrooms, what the Australian Building Code says about it, and when a window is necessary. We’ll also walk you through the best window options for bathrooms, along with their pros and cons, and when to consider upgrading your current bathroom space.
Why ventilation is important in bathrooms
Bathrooms are high-moisture environments. Every time you take a shower, run a bath, or even use hot water at the basin, water vapour is released into the air. Without adequate ventilation, this moisture builds up over time, leading to:
- Mould and mildew growth
- Damage to paintwork, plaster and cabinetry
- Structural deterioration from trapped humidity
- Poor air quality that affects your health
Proper ventilation allows moist air to escape and fresh air to circulate, which helps keep surfaces dry, prevents condensation on mirrors and windows, and preserves the lifespan of your bathroom fixtures.
While mechanical fans are often used, a window provides passive, natural ventilation and daylight, both of which are valuable in small or enclosed spaces.
However, whether a window is required by law depends on a few specific building regulations.
Australian building code requirements for bathroom ventilation
In Australia, all residential buildings must comply with the National Construction Code (NCC), formerly known as the BCA (Building Code of Australia). According to NCC Volume Two, Part 3.8.5 – Ventilation, all bathrooms must have some form of ventilation, but the method varies depending on the layout and design of the space.
There are two main ways to meet compliance for bathroom ventilation:
- Natural ventilation through windows or openings to the outside air
- Mechanical ventilation using an exhaust fan or similar system
If you’re relying on natural ventilation, the bathroom must have:
- An openable window, skylight, or vent with a minimum opening of 5% of the floor area of the room.
For example, if your bathroom is 6m², the window must have an openable area of at least 0.3m².
If you’re using mechanical ventilation, the system must:
- Vent directly to the outside of the building (not just into the roof cavity)
- Provide sufficient airflow to remove moisture effectively
These requirements apply to both new builds and major renovations. For older homes, especially those built before these codes were introduced, compliance may be required during retrofitting or refurbishment
When is a window required in a bathroom?
So, do bathrooms need windows under Australian law? The short answer is: only if you’re relying on natural ventilation.
If your bathroom does not include an exhaust fan or mechanical ventilation, then yes—a window is required.
But if your bathroom has a compliant exhaust fan that vents to the outside, a window is not legally necessary. However, many homeowners still choose to include a window for natural light, airflow, and overall comfort.
Here’s when you’re most likely to need or want a bathroom window:
- In older homes without exhaust fans or ducted systems
- In areas where power outages are common, making mechanical ventilation unreliable
- To meet NCC minimum ventilation for natural airflow
- When renovating, and you’re aiming for better energy efficiency, aesthetics or resale value
- For passive design strategies that reduce your reliance on artificial lighting and cooling
Best window options for bathrooms
Not all windows are ideal for bathrooms. Privacy, durability, and ventilation all need to be considered when selecting the right glass and frame.
At WA Custom Glass, we help homeowners and builders choose from a range of customisable glass window styles to suit bathrooms of all sizes.
Here are some of the most popular and effective options for bathroom spaces:
Awning windows
- Hinged at the top, these windows open outward from the bottom, allowing ventilation even during light rain.
- Great for tight spaces and can be placed high on the wall for privacy.
- Pair well with obscure glass for added discretion.
Sliding windows
- Classic and functional, sliding windows are easy to operate and ideal for larger openings.
- When fitted with obscure or frosted glass, they balance airflow and privacy.
Fixed windows (in combination)
- Often used in combination with an exhaust fan, smaller operable window or skylight.
- Ideal for bringing in light while preserving wall space for tiling or cabinetry.
All our bathroom window options can be customised for colour, hardware, and glazing. We also offer bushfire-rated options, energy-efficient glazing, and safety glass, ensuring compliance with both local laws and homeowner expectations.
Pros and cons of bathroom windows
If you’re on the fence about whether or not to include a window in your bathroom, it’s worth weighing up the benefits and drawbacks.
Pros:
- Natural ventilation reduces humidity and prevents mould
- Natural daylight reduces reliance on artificial lighting. Also great if you like to have plants in your bathroom!
- Increased comfort with fresh air circulation
- Energy efficiency when used as part of a passive design strategy
- Aesthetic appeal, adding character to your space
Cons:
- May compromise privacy if not positioned or treated properly
- Can reduce wall space for shelving, mirrors or tiles
- Needs occasional cleaning to remove moisture or soap build-up
- Can be a source of draughts or heat loss if not double-glazed or sealed well
That’s why WA Custom Glass always recommends working with experienced glaziers to find the perfect balance between aesthetics and functionality.
When to consider window replacements and upgrades
Even if your bathroom already has a window, it might not be serving its purpose well.
Older timber frames, single-pane glass, or poorly placed windows may be inefficient or non-compliant with current standards.
Here’s when it might be time to upgrade:
- Persistent condensation, even with a window present
- Visible mould around the frame or sill
- Cracked or damaged glass
- Poor sealing leading to draughts or water leaks
- Outdated style that affects the look of your home
- Renovating the bathroom and aiming for better ventilation or energy ratings
At WA Custom Glass, we specialise in custom bathroom window replacements using our proprietary removal and installation technique. This ensures a clean, efficient process with minimal disruption—and every product we install comes backed by our 10-Year Replacement Warranty.
We work with Jason Windows, a trusted, locally owned manufacturer, to ensure your bathroom windows are built for WA’s unique climate and conditions.
What about bathroom windows in strata and rental properties?
For strata properties and rentals, bathroom windows must also comply with the NCC and any local council regulations. If you’re a real estate agent, landlord, or strata manager, it’s important to ensure all bathrooms have compliant ventilation systems, whether via windows or mechanical systems.
WA Custom Glass offers a dedicated service stream for strata and real estate clients, including window inspections, replacements, and upgrades—ensuring your properties are safe, up-to-code, and tenant-friendly.
How to choose the right bathroom window
When selecting or replacing a bathroom window, consider the following:
- Ventilation requirements: Are you relying on natural airflow?
- Window placement: Will it be high enough for privacy but still allow light?
- Glass type: Do you need frosted, textured, tinted, or double-glazed options?
- Bushfire rating: Is your home in a BAL-rated zone?
- Frame colour and material: Match the aesthetics of your home.
- Security: Does the window need locks or safety features?
WA Custom Glass provides free quotes and consultations to help guide you through the process. Our expert team can recommend the right solutions based on your bathroom’s size, orientation, and style.
Making the right choice for bathroom windows in WA
So, do bathrooms need windows in Australia? The short answer: not always—but they’re often a smart inclusion.
Whether for natural ventilation, building code compliance, or simply a better bathroom experience, windows can make a big difference. And with the right design, they can add both form and function to one of the most important spaces in your home.
If you’re building, renovating, or managing a property in WA, and need expert advice on bathroom windows, reach out to the team at WA Custom Glass.
As WA’s first AGGA-accredited glazing company, we bring over a decade of experience in custom window retrofitting, replacements, and installations. We take pride in delivering reliable, long-lasting solutions.
