As the seasons change, many Surrey homeowners begin to notice a familiar nuisance: condensation on double glazed windows. Misted glass, damp patches around window frames and water collecting on sills are all tell-tale signs that the balance between your indoor air and window insulation is off.
This problem becomes especially common in autumn, when cooler nights and warm interiors collide. Left untreated, condensation on the inside of your window panes can lead to mould, cause damage to frames, and even affect your health.
However, County Secure can help. Based in Surrey, we specialise in keeping homes warm, energy efficient and secure. Our team specialises in professional window and door repairs, offering everything from glass replacement and draught proofing to lock repairs and high-quality window sealant work.
With years of hands-on experience, our approach is simple: fix problems quickly, neatly and with lasting results. In this article, we will explain what window condensation is, why it becomes worse in autumn, and how you can stop condensation on windows with the right measures.
What is Window Condensation?
Condensation is the process where water vapour in the air turns into liquid droplets when it touches a colder surface. Exterior condensation on your windows is usually just dew, but interior condensation on double glazed windows can be problematic.
Interior condensation occurs because the warm air inside many homes holds moisture from activities like cooking, showering, and drying clothes. When this moist air meets a cooler surface, such as a windowpane, the excess water vapour condenses and forms droplets on the glass. You see it most often on surfaces like windows, because glass cools faster than other materials in your home.
Occasional condensation is normal, but when it becomes persistent it is a sign that humidity levels are too high or that your windows sealant is not fully effective.
Why Condensation Gets Worse in Autumn
Understanding what condensation is makes it easier to see why autumn in the UK, with its cooler nights and increased indoor humidity, is the season when this problem often gets worse.
Temperature Difference and Dew Point
Condensation occurs when warm, moist indoor air meets a cooler surface. The temperature at which this happens is called the dew point. During autumn, the air outside gets colder at night while heating is turned on indoors. This bigger difference in temperature makes condensation on glass more likely to appear in the mornings.
Higher Indoor Humidity
In autumn, homes are often sealed up tightly against the cold. Windows are kept closed (trapping moisture from daily activities like showering and cooking), clothes are mostly dried inside, and heating produces more warm air. Without proper ventilation, this creates ideal conditions for condensation on double glazed windows.
Efficient Glazing and Cold Frames
Modern double glazing keeps heat inside your home effectively, but the outer window glass can remain cold, which is more likely to cause condensation. Older aluminium frames also conduct heat away quickly, creating cold edges where moisture collects. In this case, proper window sealant is vital to help reduce the risk of condensation.
Why Condensation Matters
Condensation is more than just a cosmetic problem. Persistent moisture can damage timber frames, cause wallpaper to peel, and lead to mould growth. Mould not only looks unsightly, but can adversely affect indoor air quality and even cause breathing difficulties or other health issues. Over time, untreated damp can also harm plaster and weaken the structural elements around windows.
Draught proofing windows, using effective window sealing products, and improving airflow can prevent these issues from taking hold before they cause long-term problems.
How to Stop Condensation on Windows
Improve Ventilation
Air circulation is key to be able to stop condensation on windows. Use extractor fans in kitchens and bathrooms, open trickle vents, and occasionally crack open a window for a few minutes to refresh the air. Even small bursts of ventilation can help reduce moisture indoors.
Control Humidity Levels
The ideal indoor humidity is between 40 and 60 per cent. Simple humidity meters can be bought cheaply and show if your levels are too high. If they are, consider a dehumidifier to bring them down. For a quick fix, bowls of salt can also absorb small amounts of excess moisture.
Maintain Consistent Heating
Keeping your home at a steady temperature helps reduce condensation on double glazed windows, as large fluctuations in heat encourage moisture to settle on glass. According to experts, it is best to keep rooms between 18°C and 21°C to avoid damp, mould, and condensation.
Use Window Sealant and Draught Proofing
Cracks or gaps around window frames let in cold air, making condensation worse. Applying silicone window sealant around frames blocks these gaps and prevents draughts. Professional draught proofing with high quality products such as Q-Lon foam seals ensures a tighter fit and better insulation. This can reduce heat loss by up to 50%, keeping your home warmer and drier.
Clean Condensation Effectively
Wipe away condensation each morning with a dry cloth or use a window vacuum. This stops water sitting on the sill and reduces the chance of mould forming. However, regular cleaning does work best when paired with proper window sealing.
How County Secure Helps
At County Secure, we specialise in practical solutions that keep your home warm, efficient and free from condensation. Our team provides professional window sealing and draught proofing services across Surrey and the surrounding areas, using durable silicone and Q Lon seals for long lasting protection.
The benefits of draught proofing windows include lower energy bills, better air quality, improved comfort and windows that stay clearer through the colder months.
Frequently Asked Questions
Q: Why does condensation appear inside more than outside?
A: Because indoor air is warmer and holds more moisture. When it touches the cold inner surface of glass, droplets form.
Q: Will sealing windows reduce ventilation too much?
A: No. Professional draught proofing focuses on blocking unwanted gaps while keeping trickle vents and extractor fans working properly.
Q: Can DIY window sealant fix condensation?
A: DIY can help in the short term, but expert window sealing and draught proofing provide a longer lasting solution.
Q: When should windows be replaced instead of repaired?
A: If condensation appears between panes of glass, it means the seal has failed. In that case, window glass replacement may be the best option.
Q: Does mould from condensation need professional removal?
A: Small areas can be cleaned safely, but the cause of the condensation must be treated first to stop it coming back.
Keep Your Home Comfortable This Autumn
Condensation is a common problem in autumn, but it is not one you need to live with. By improving airflow, maintaining steady heating, and draught proofing with high-grade window sealant, you can keep your home comfortable and energy efficient.
If you are struggling with condensation or worried about draughts, contact us today for expert advice and a no obligation quote. We will help you find the right solution to stop condensation on windows and keep your home warm this season.
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