Condensation on windows: how to stop condensation on inside of windows - what causes it?

• Warm, moist air meeting cold window surfaces creates water droplets, especially in winter
• Open windows, use extractor fans and dehumidifiers to reduce indoor humidity.
• Double glazing, thermal curtains and insulating films can also help to prevent condensation
• Better insulation also reduces energy bills and avoids costly repairs from mould and damage

Condensation on windows is a common issue in homes, especially during the colder months.

But while it may seem like a minor inconvenience, persistent condensation can lead to a range of problems, including dampness, mould growth and even structural damage.

So how can you effectively stop condensation on your windows, what are the potential savings in terms of energy bills, and how can addressing the issue save you money in repairs and maintenance?

Why does condensation form?

Condensation forms when warm, moist air comes into contact with a cold surface, like your window glass. The moisture in the air turns into water droplets on the surface of the window.

This typically happens in the winter when the difference between indoor and outdoor temperatures is more significant. Factors such as cooking, showering, drying clothes, and even breathing can introduce excess moisture into the air inside your home.

How can I stop condensation?

The presence of condensation on the inside of windows can be a sign of poor ventilation, and when air doesn't circulate freely, humidity builds up, and windows become the first place to show the effects.

As such, proper ventilation is one of the most effective ways to control humidity levels and reduce condensation, so open windows periodically, even in winter, to allow fresh air to enter and moisture to escape.

Install extractor fans in moisture-prone areas like kitchens and bathrooms - these can help to remove excess humidity from the air before it can condense on your windows.

You could also consider using a dehumidifier to reduce moisture in the air, especially in areas where condensation is a persistent problem, such as basements or bedrooms.

Improving the insulation of your windows can also help keep the glass warmer, reducing the likelihood of condensation.

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Double or triple-glazed windows provide an insulating barrier that reduces the temperature difference between the inside and outside of your window. This helps keep the window surface warmer, preventing moisture from condensing.

Thermal curtains or blinds can help maintain a more stable indoor temperature and prevent cold air from affecting the windows. Applying a thin insulating film on the windows is another cost-effective way to reduce condensation.

By addressing the sources of excess humidity inside your home, you can significantly reduce the chances of condensation forming on your windows.

Cook with lids on pots and turn on exhaust fans while cooking to prevent excess steam from lingering in the air. Dry clothes outside or use a tumble dryer that vents to the outside, rather than air-drying clothes indoors.

Use moisture absorbers in areas like closets or storage spaces where moisture tends to accumulate.

Air leaks around windows can also contribute to condensation by allowing cold air to enter and cause temperature differences between the inside and outside of the window.

What are the financial benefits of preventing condensation?

While condensation may seem like a simple problem to tackle, the long-term benefits of addressing it are significant - especially in terms of saving money on energy bills and preventing expensive repairs.

If your windows are not properly insulated, your heating system also has to work harder to maintain a comfortable temperature inside. Cold air entering through gaps or poorly insulated windows means your heating system consumes more energy.

By improving your windows’ insulation, you can reduce heat loss, thereby cutting down your heating costs.

Condensation can also lead to mould growth and rotting wood around window frames, resulting in costly repairs. Mould thrives in damp conditions, and if condensation is left unchecked, it can seep into walls, floors, and even the foundation of your home, which can result in expensive structural repairs.

Windows with persistent condensation may also need to be replaced if they become damaged. Double-glazed windows can fog up when the seal breaks due to excessive moisture, making the window less efficient and more costly to replace.

Homes with well-maintained windows and energy-efficient features are more attractive to potential buyers, and if you invest in improving your window insulation and reducing condensation, you are likely to see an increase in your property’s value.

Have you struggled with condensation on your windows? What tips and tricks have worked for you, or are you planning to try any of the methods mentioned here? Share your thoughts and experiences in the comments.