Does Drying Clothes Indoors Cause Mould?

It is a scenario every Melburnian knows. It is the middle of July, it has rained for three days straight, and the school uniforms are still wet. So you drag the clothes horse into the living room, crank up the heater and shut the door. It feels cosy and sensible — but drying clothes indoors is one of the leading causes of seasonal mould.

From a building-science point of view, drying laundry indoors without proper ventilation is close to throwing a bucket of water at your walls and ceiling. It feels like a temporary necessity, yet it creates a moisture load — the total amount of water vapour released into the air — that most modern, sealed homes simply cannot cope with.

The Science: Where Does the Water Go When Drying Clothes Indoors?

When your clothes dry, the water does not disappear — it changes state, turning from liquid water in the fabric into water vapour (an invisible gas) in the air. The Australian Government’s Your Home guide confirms that washing and drying clothes adds a high level of water vapour to indoor air, and a single load can release litres of moisture over the course of drying.

Without a way to extract that moisture — an exhaust fan or open window — it stays trapped inside. The warm, moist air drifts until it meets a cold surface: a glass window, an uninsulated external wall, or the cool plasterboard behind a wardrobe. The instant it touches that cold surface it turns back into liquid water as condensation, creating the perfect petri dish for mould spores to germinate.

The Consequences: More Than Just Condensation on Windows

You might wipe the windows each morning and assume the problem is solved. But water vapour behaves like any gas — it spreads everywhere, and the damage reaches well beyond the glass.

1. Increased Risk of Dust Mites

Mould is not the only pest that loves a humid home. The National Asthma Council warns that dust mites thrive once indoor humidity climbs high, and that lowering it can help control them. Drying clothes inside creates an ideal breeding ground for mites in carpets, sofas and bedding — a major trigger for asthma and allergies.

2. Higher Heating Bills

This consequence catches many people out. Damp air is harder to heat than dry air, so a room full of laundry moisture forces your heater to work overtime to reach a comfortable temperature — quietly inflating your winter power bill.

3. Surface Mould on Belongings

Ever found white or green fuzz on leather shoes or winter coats in the wardrobe? High humidity equalises throughout a room, so even if the clothes horse is in the lounge, the moisture migrates to cool, stagnant spots like the wardrobe and settles on organic materials such as leather and cotton. Knowing whether mould-affected clothing and shoes can be saved or should be tossed becomes a regular question once this pattern sets in.

How to Prevent Mould When Drying Clothes Indoors

Drying outside is not always possible in Melbourne, so if you must dry indoors, the goal is to manage the moisture rather than let it loose in the house.

The “Closed Room” Method

Never dry clothes in the main living area where you spend your time. Instead, put the rack in a small room such as a laundry or spare bathroom, close the door to the rest of the house, and open a window. This gives the moisture a path of least resistance to escape outside rather than soaking into your plasterboard. Pairing this with good winter ventilation habits in your wet rooms makes a noticeable difference within weeks.

Use a Dehumidifier

For renters and homeowners alike, a good compressor dehumidifier is one of the best investments you can make for your home’s health. Many units include a “laundry mode” that actively pulls moisture out of the clothes and collects it in a tank before it can settle on your walls — effectively a tumble dryer for the whole room, at a fraction of the running cost. It does help, though, to understand exactly how dehumidifiers can stop mould growing back — and where their limits lie.

Check Your Dryer Venting

If you use a standard tumble dryer, make sure it is vented to the outside. A dryer that simply blows warm, wet air into the laundry is pumping litres of water into the house every cycle. A condenser or heat-pump dryer, which captures the water in a tank or drain, avoids this entirely.

Signs High Indoor Humidity Has Already Caused Damage

If you have dried clothes indoors for years, you may already have a long-term problem. Watch for these warning signs:

• Musty smells. A persistent damp odour in the drying room even when it is empty.
• Peeling paint. Especially on the ceiling directly above where the rack usually sits.
• Shadowing. Dark patches forming on the cornices or in the corners of the room.

A lingering musty odour is often the first clue, and understanding what causes that musty smell in a house can tell you whether the moisture has moved from a nuisance into the building fabric itself.

Conclusion

You do not have to let your laundry rot the house from the inside out. By managing moisture with ventilation and a dehumidifier, you can get through a Melbourne winter without inviting mould into your living room.

If you have already stopped drying clothes indoors but the mould keeps returning, the moisture may have penetrated the plasterboard or structure, and cleaning alone will not resolve it. At that point, having the home checked for hidden structural dampness is the logical next step to find out exactly what is feeding the problem.

Frequently Asked Questions (FAQs)