Why Does Mould Grow Around Windows

By Ruth MacEachern

Product Manager

Mould growth around windows can be a problem in many homes. As well as being an unpleasant sight, it can cause damage to surfaces, and more importantly, poses health risks, such as respiratory issues and allergies. Understanding why mould tends to grow around windows can help you take preventive measures to keep your home mould-free.

The role of condensation

The most common cause for mould growing around windows is condensation. Condensation occurs when warm, moist air meets a cooler surface, such as a window. As the air cools, it can no longer carry as much water vapour, and the moisture in the air turns into liquid droplets on the glass.

As this water pools at the bottom of the window, it can create a persistent damp area where mould to thrive. This is particularly common in colder months when the temperature difference between indoor and outdoor air is more pronounced.

What causes condensation

Several factors contribute to the formation of condensation around windows:

Limited airflow around windows means that the air is left in contact with a cold surface for longer, and more moisture is released as a result. Similarly, poor insulation or single glazing means that the temperature around windows is much colder than the ambient room temperature, which causes a steeper heat gradient and causes more water vapour to be released as condensation.

The humidity levels in your home are affected by activities such as cooking, showering, and drying clothes indoors. The more steam that is released into the air and not ventilated, the higher the humidity levels, which means more condensation.

How you can reduce humidity, and stop mould for good

To prevent mould growth around windows, it's essential to reduce humidity levels in your home.

There are easy steps you can take to reduce humidity: Avoid drying clothes indoors or leaving towels on radiators; use pan lids when cooking on the stove to reduce the amount of steam released into the air; and make sure that you close the bathroom door when taking a shower.

If you have condensation problems, ensure that you wipe down windows and windowsills to remove any moisture buildup in the morning. This will help to take away the conditions that help mould to thrive and reduce the problem in the short term.

Improving the ventilation in your property is the single most effective way of stopping condensation. Ensuring that you have properly installed extractor fans in kitchens and bathrooms to will help to ensure that much of the moisture in the air is removed before it can spread from the source and cause condensation to form in other rooms.

Do you have a problem with mould around your windows?

Simply cleaning mould from surfaces is only a temporary solution, and the mould will grow back and could pose a risk to your health. Get help today from one of EnviroVent’s local ventilation specialists. Book a free home survey by filling in your postcode below and get advice and support about how you can reduce condensation and mould in your home and improve your indoor air qualit