It is a scenario every Melburnian knows well. It’s the middle of July, it has been raining for three days straight, and the school uniforms are still wet. Running the tumble dryer all day costs a fortune, so you drag the clothes horse into the living room, crank up the heater, and shut the door.
It feels like a sensible, cozy solution. But from a building science perspective, you might as well be taking a bucket of water and throwing it onto your walls and ceiling.
Drying clothes indoors without adequate ventilation is one of the leading causes of seasonal mould growth in Victoria. While it seems like a temporary necessity, this habit creates a moisture load that most modern homes simply cannot handle.
The Science: Where Does the Water Go When Drying Clothes Indoors?
When your clothes dry, the water doesn’t disappear; it simply changes state. It transforms from liquid water in the fabric into water vapour (gas) in the air.
According to the Australian Government’s ‘Your Home’ guide, a single load of wet laundry can release significantly large amounts of moisture into your home. Estimates suggest a full load of washing can release between 2 to 5 litres of water into the indoor air.
If you don’t have a way to extract that moisture (like an exhaust fan or open window), it remains trapped inside. Eventually, that warm, moist vapour travels until it hits a cold surface—usually a glass window, an uninsulated external wall, or the cool plasterboard behind a wardrobe.
The moment it hits that cold surface, it turns back into liquid water (condensation), creating the perfect petri dish for mould spores to germinate.
The Consequences: More Than Just Condensation on Windows
You might wipe the condensation off your windows in the morning and think the problem is solved. However, moisture vapour behaves like a gas—it penetrates everywhere.
1. Increased Risk of Dust Mites
Mould isn’t the only pest that loves a humid home. Sensitive Choice (National Asthma Council) warns that house dust mites thrive in environments with high relative humidity. By drying clothes inside, you are creating an ideal breeding ground for mites in your carpets, sofas, and bedding, which is a major trigger for asthma and allergies.
2. Higher Heating Bills
This is a consequence few people realize. Damp air is much denser and harder to heat than dry air. If your home is full of laundry moisture, your heater has to work significantly overtime to bring the room up to temperature, leading to “bill shock” at the end of winter.
3. Surface Mould on Belongings
Have you ever found white or green fuzz growing on your leather shoes or winter coats in the wardrobe? This happens because high ambient humidity equalizes throughout the room. Even if the clothes horse is in the lounge, the moisture migrates to cool, stagnant areas—like your wardrobe—and settles on organic materials (leather and cotton).
Best Practices: How to Prevent Mould When Drying Clothes Indoors
We understand that in Melbourne, drying clothes outside isn’t always an option. If you must dry indoors, you need to manage the moisture mechanically.
The “Closed Room” Method
Never dry clothes in the main living area where you spend your time. Instead, place the drying rack in a small room (like a laundry or spare bathroom), close the door to the rest of the house, and open a window. This creates a path of least resistance for the moisture to escape outside rather than into your plasterboard.
Invest in a Dehumidifier
For Melbourne renters and homeowners alike, a good compressor dehumidifier is arguably the best investment you can make for your home’s health.
Consumer advocacy group Choice.com.au recommends using dehumidifiers with a specialized “Laundry Mode.” These machines actively pull the moisture out of the clothes and collect it in a tank, preventing it from settling on your walls. They essentially act as a tumble dryer for the whole room, but at a fraction of the electricity cost.
Check Your Dryer Venting
If you use a standard tumble dryer, ensure it is vented to the outside atmosphere. If your dryer just blows warm air into the laundry room, you are pumping litres of water into the house every cycle. Consider upgrading to a Condenser or Heat Pump dryer, which captures the water in a tank or drain.
The Signs: How to Check When High Indoor Humidity Has Already Caused Damage
If you have been drying clothes indoors for years, you may have created a long-term problem. Look for these warning signs:
- Musty Smells: A persistent damp odour in the room where you usually dry clothes, even when the room is empty.
- Peeling Paint: Especially on the ceiling directly above where the drying rack usually sits.
- Shadowing: Dark patches forming on the cornices or in the corners of the room.
Conclusion
Don’t let your laundry rot your home from the inside out. By managing moisture with ventilation and dehumidifiers, you can survive a Melbourne winter without inviting mould into your living room.
However, if you have stopped drying clothes indoors but the mould keeps returning, the moisture may have already penetrated the plasterboard or structure. At this stage, cleaning won’t help. Contact Mould Busters Melbourne for a professional inspection to check for structural dampness and ensure your home is safe.
Frequently Asked Questions
Does using a heater help prevent mould when drying clothes?
Not necessarily. A heater warms the air, allowing it to hold more moisture, but it doesn’t remove the water. Unless you also open a window to let that warm, wet air escape, it will simply condense on the walls as soon as the heater turns off.
Do I really need a dehumidifier in Melbourne?
Given Melbourne’s high humidity and cold winters, a dehumidifier is highly recommended. It is the most effective tool for controlling indoor moisture levels and drying laundry without causing condensation issues.
Why is there mould in my wardrobe even though I don’t dry clothes there?
Moisture vapour travels. If you dry clothes in the bedroom, the humidity in that room rises. The vapour will migrate to the coolest, darkest place with poor airflow—which is usually the inside of your wardrobe—and settle on your shoes and clothes.