Potted plant in front of a glass window covered in condensation

24th January 2024

How To Stop Condensation on Windows

A shared frustration throughout the UK during autumn and winter is the constant presence of condensation on our windows and in our houses. Be it due to old windows, too many hours with the heating on or damp problems elsewhere in the house, at least a couple of condensation circumstances are unavoidable.

However, condensation inside windows can be frustrating and potentially damaging if left unchecked for too long, and there are ways to stop it. Let’s talk about what it is, its causes and what we can do to prevent condensation on windows.

What is condensation?

Simply put, it’s water that is created when warm air hits a cold, hard surface. Think of a cool glass of lemonade and ice sitting outside on a hot day, those droplets that form on the side of the glass are condensation.

What causes condensation on windows?

Condensation on windows is due to the cold air outside cooling the glass window panes and then the warm air from inside – whether it’s from heating, cooking, bathing or drying wet clothes – hits the cold glass of the window and forms water droplets.

Why is condensation worse in winter?

In the UK and other places with similar climates, you will notice that condensation is worse during the winter months. This is because with fewer hours of sun to warm them and cooler temperatures outside, our glass windows get much colder. We then turn our heating on and dry our clothes inside, creating more warm air, which touches the cold windows and turns into water.

How does condensation cause damage?

The build-up of water on your windows can cause long-lasting problems including black mould, damp and window frame damage. Most window frames are made of wood or uPVC (Unplasticised Polyvinyl Chloride), both of which can eventually be damaged by water in different ways.

Wooden windows

Wooden frames are usually painted and varnished. The repeating pattern of getting wet and then drying out will cause the wood to split and the paint and varnish to crack and peel off. If wooden window frames are constantly wet then they could rot, requiring a full replacement.

uPVC windows

uPVC, while designed to be tough, cannot handle the constant soaking and drying that occurs when condensation forms and then dries in the sun. This makes uPVC susceptible to damage from nighttime condensation. The seal keeping the double glazing in place will dry and crack which can lead to moisture forming within the gap between the panes. This fogging up between the glass renders the double glazing useless and it will need to be replaced.

How can I stop condensation?

Luckily, there are many routes you can take to stop excess water from forming on the inside of your windows, with most of them requiring no extra spend. 

Open windows when cooking and bathing

If you can cope with the slight drop in temperature, keeping your windows ajar when cooking and bathing is a great way to reduce the risk of condensation. Things like whipping up a delicious dinner and showering the stress of the day away inevitably create steam, and this warm air hitting the cold windows causes a lot of instant condensation.

By keeping your windows slightly open, that steam can escape, greatly reducing the chance of condensation.

Keep your curtains open

This may sound a little counterproductive as warm air hitting your cold windows is the main cause of condensation, but closing your curtains can actually make it worse.

By closing your curtains, you are blocking any heat from getting to the window, meaning the glass will get very cold. When you eventually open the curtains and the warm inside air hits the window, the condensation will be far worse than it would have been had the curtains stayed open. 

This isn’t possible for everyone, as some can’t sleep without total darkness, but if you’re able to, keep curtains open so that your heating can consistently warm your windows. 

Fix any damp problems 

If you have any areas of dampness in the home that aren’t caused by condensation, get them sorted. Damp releases humidity into the air, contributing to condensation, which can start a vicious cycle.

Purchase dehumidifiers or moisture absorbers

There are tools you can buy that aid in preventing wet windows. Dehumidifiers are machines that draw the humidity from the air, and they tend to range from the tens to the hundreds in cost. These are very useful, reusable, and can be a great help in reducing condensation.

Window condensation absorbers are much more affordable than dehumidifiers. They are often small and can be placed on windowsills and other surfaces, with gels or hard powders inside that draw moisture out of the air. They need to be thrown out once used or refilled with each use, but they do a good job of preventing condensation when near windows.     

Keep your heating on a constant low temperature

If you’re able to, keeping your heating on low can help reduce condensation problems. By having your home at a consistent temperature, your windows are less likely to get cold when the heating turns off. When the heating suddenly comes back on, the air rises in temperature quickly but the window glass doesn’t, inevitably creating condensation.

Replace single-glazed windows with double-glazed windows

Single glazing attracts condensation. The glass is thin and quick to cool, so any warm air that hits it is going to immediately turn to water. Single-glazed homes tend to be colder and more damp, and this window type is often attributed to older, outdated buildings.

By upgrading to double glazing, you’ll be putting preemptive measures against condensation in place. Double glazing consists of two panes of glass with a gap between them to insulate. All of this is then sealed so no moisture can enter the gap. This inner pocket acts as a thermal buffer and greatly reduces the chance of condensation by keeping the window closer to indoor temperatures.

Replace damaged double-glazed windows

If your windows are double-glazed and you spot condensation between them, it means the seals have failed. These will need to be replaced or not only will you get condensation, but your home will get colder as the windows will lose the ability to keep any heat in. Check to see if your windows are still under warranty and get them replaced. 

Is summer morning condensation an issue?

No, if you spot droplets on the outside of your windows on warmer mornings, this is nothing to worry about. This sort of condensation is not a problem and will not cause any damage. It occurs when the humid air outside is warming quickly while your windows are still cold from the night. This condensation evaporates quickly, so don’t worry if you spot it.

Upgrade to double-glazed windows to prevent condensation

At Norwich Glass Company, we understand how important it is for your home to be comfortable. If your windows are old or damaged, consider upgrading them to new double-glazed units to keep the heat in and reduce condensation. 

Are you interested in updating your windows? Our expert team is on hand to answer your questions and give advice. Simply give us a call today on 01603 431409 or select an option under ‘double glazed units’ in our easy-to-use online enquiry form.

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