How to Stop Condensation on Double-Glazed Windows in the Winter

Condensation on your windows can be a nuisance in the colder months, and it can lead to some serious problems if left untreated. 

From causing damage to furniture and your windows themselves to promoting the growth of mould which can be detrimental to your health, eliminating the root causes of condensation is the only way to stop condensation-related problems from happening. 

It is essential to understand what is normal and what isn’t when it comes to condensation. 

Brand-new double-glazed windows should not generate condensation; however, if there is condensation build-up between the two panes of glass, it could be the case that your windows are faulty. 

In other cases, the first step is figuring out what could be causing excessive moisture levels in your home.

What Causes Condensation on Windows in the Winter?

Condensation occurs when excess moisture in the air comes into contact with a cold surface – typically appearing on windows when it’s colder outside than inside the home. 

Air contains microscopic water droplets that are invisible to the naked eye. When humidity rises within the home, the water content of the air becomes more concentrated which increases the risk of it manifesting on surfaces. 

A similar phenomenon can be observed in the summer, where a glass of ice-cold water will look as if it is sweating due to the moisture in the hot air colliding with the surface of the glass of water. 

In contrast to warm air, where water molecules are spaced far enough apart to ‘hold’ the moisture, cold air has water molecules ‘come together.’ When this happens, they will merge into visible liquid. This is also known as the dew point. 

Some examples of the dew point include: 

• Condensation on a mirror after a hot shower
• A kitchen window steaming up when cooking without adequate ventilation
• Moisture appearing on windows when drying clothes inside without airflow

Condensation can also form on surfaces other than your windows, especially in areas where moisture can become easily trapped. These include: 

• Windows that have curtains or blinds, which can in turn lead to mould build-up
• Behind large pieces of furniture against a cold wall
• Within a fitted wardrobe on an external wall

What to do if Your Double Glazing Has Condensation on the Outside

Condensation on the outside of your windows can generate when the air outside is warmer than the temperature of your windows. If it is appearing outside, your windows are effectively preventing heat transfer – meaning that they are working correctly and insulating your home. 

If you find the look of condensation outside unsightly, you can simply wipe it away if your windows are within reach. In most cases, however, the condensation will evaporate as the day goes on and the sun shines onto your windows.

What to do If Your Double Glazing Has Condensation on the Inside

Condensation on the inside of your windows can result from excess water molecules in the air from hot showers, steam from cooking, or kettles boiling. In this instance, the best thing to do is to wipe it away and increase the ventilation in your home whilst using steam-producing appliances. 

If there is condensation on your windows outside of using these appliances, this can indicate the humidity levels within your home are above average and you may have an issue with ventilating your property.

If water vapour has nowhere to go, condensation can not only appear on your double glazing, but also on your walls, on your furniture, and within your carpets. 

Having excess moisture around your home can be detrimental to your health too, due to the increased risk of mould growth. 

To prevent condensation and reduce the growth of mould, it is a good idea to encourage airflow around your home by letting in the fresh air and improving ventilation.

5 Ways to Easily Ventilate Your Home

• Open doors and windows when the central heating is off. Only do this periodically in the winter to keep the heat in.
  
• Dry your laundry outside, or make sure your tumble dryer vent is placed outside a window
  
• Keep your windows on the night vent latch if they are behind thick curtains or above a radiator. This keeps your home secure whilst promoting airflow.
  
• Keep internal doors open when not cooking or showering.

What to do if Your Double Glazing Has Condensation in the Panes

The generation of condensation between the panes of your double-glazed windows indicates that they are not doing their job properly. 

The air-tight seal which prevents the insulating gas inside the window has failed, meaning the gas has been let out and replaced with air. 

When this happens, the air becomes trapped and heated – resulting in water vapour appearing between the panes of glass. 

Not only can this cause further damage to the window, but it can also dramatically reduce how energy efficient your windows are as they no longer reduce heat transfer between the inside and outside of your home. 

If this is happening to you, the only solution is to replace your windows with brand-new double glazing if they are outside of their warranty period. If they are within the warranty period, you will need to contact your window installer to get a replacement.

How to Stop Condensation on Double-Glazed Windows in Winter

A lack of ventilation is a primary cause of condensation and mould growth. 

Previously, homes in the UK were fitted with poorly installed windows, doors, chimneys, and air vents, all of which promoted the circulation of air. 

Modern technology has enabled us to build considerably more energy-efficient homes over the last 30 years, however, this has caused modern homes to effectively become sealed units which trap moisture inside, eliminating their natural ventilation capabilities. 

There are a few options available that can improve the ventilation in your home.

Airflow Systems

Many new builds are built with internal airflow systems which combat ventilation problems. They use a network of ducts in the ceiling which exchange air from the outside to the inside. 

These systems are great at maintaining good air circulation and a balanced humidity, especially when the property is well-sealed. 

The installation of airflow systems can be an expensive and time-consuming process, and it may not be possible to install them in older or listed buildings.

PIV Units

Positive Input Ventilation (PIV) units can be fitted in areas which see a lot of moisture being produced; like bathrooms, kitchens, and damp basements. 

These are relatively easy to have installed and are designed to extract humid air from inside the home whilst drawing in dry air from the outside. This exchange of air helps to maintain a healthy humidity balance in the home.

Extractor Fans

It is essential to have sufficient extraction in a bathroom to reduce excessive humidity produced by showers. 

Some extractor fans are designed with humidity controls which allow the fan to operate automatically if high humidity levels are detected. 

Extractor fans are also a good idea for kitchens as they help to remove smoke and smells as well as excessive moisture.

Air Vents or Air Bricks

Air bricks often get blocked off to prevent draughts, however, they do work to keep an area sufficiently ventilated. 

A simple air vent can manage the humidity levels within a room, however, this can also result in the reduced energy efficiency of the home. 

Air vents in windows also help with ventilation and can put a stop to condensation being formed inside the window.