Nothing beats the crisp, fresh smell of linens dried outdoors. Unfortunately, in many places you can only enjoy that scent during warmer months. When winter arrives, clothes often end up drying inside — and with that comes an unpleasant, musty odor. This isn’t just an annoyance; it’s a sign of a deeper problem. Indoor drying raises humidity levels, creating the perfect environment for mold, dust mites, and fungi to thrive.

Scientists in the UK have studied this common habit and found that it can even trigger respiratory infections in vulnerable individuals.

Why Drying Clothes Indoors Can Be Harmful

A single load of laundry contains close to two liters of water. When clothes dry inside — whether on a rack, near a heater, or over a radiator — that moisture evaporates and is released directly into your living space. Studies show that this can increase indoor humidity by up to 30%.

That elevated moisture encourages the growth of mold spores and dust mites. For many people, this can lead to discomfort, but for those with asthma, allergies, or sensitive lungs, the impact can be far more serious.

What Experts Have Found

Professor David Denning and researchers at the National Aspergillosis Centre in Manchester report that indoor laundry drying significantly raises exposure to Aspergillus fungal spores — a major cause of respiratory infections.

According to Professor Denning:

• Most people can fight off these spores without issue.

• However, individuals with asthma, weakened immune systems, or chronic lung conditions are at much higher risk.

• In these cases, inhaling the spores can lead to pulmonary aspergillosis, a potentially permanent — and sometimes fatal — disease affecting the lungs and sinuses.

Understanding Aspergillosis

Aspergillosis refers to several conditions caused by the Aspergillus mold. While it typically affects the nose, throat, and lungs, it can spread throughout the body in severe cases.

Common symptoms include:

• Wheezing and shortness of breath

• Persistent cough

• Fever

• Chest tightness

• Sinus pain

Severe symptoms can include:

• Unexplained weight loss

• Chest pain

• Coughing up blood

Healthy individuals generally clear the spores naturally, but once the infection reaches the lungs, treatment with antifungal medication is usually necessary.

A Real-Life Example

Craig Mather, a 43-year-old father of three from Bolton, developed a serious Aspergillus-related lung infection. With a history of asthma and past tuberculosis, his lungs were already compromised.

He noticed his symptoms — coughing fits, night sweats, difficulty breathing — worsened whenever he dried wet clothes on the radiator in his bedroom. After being diagnosed with chronic pulmonary aspergillosis and eliminating indoor drying, his health dramatically improved.

Safer Alternatives to Drying Clothes Indoors

To reduce the risk of mold growth and protect your respiratory health, experts recommend:

• Drying clothes outdoors whenever possible.

• Using a tumble dryer if you have access to one.

• Drying clothes in a well-ventilated room, away from bedrooms and main living spaces.

• Opening windows after cooking, showering, or drying laundry to let moisture escape.

• Using a dehumidifier to keep indoor humidity levels under control.

Managing moisture at home isn’t just about comfort — it’s crucial for protecting your lungs and preventing hidden mold growth in your walls, carpets, ceilings, and furniture.