How to Stop Condensation on Double Glazed Windows in Winter

Condensation is one of the most common occurrences on windows in winter when there is excessive moisture in the air. While double glazing significantly reduces the likelihood of condensation, it can sometimes occur when there is a temperature difference between the warm air indoors and the cold window surface. To stop condensation on double glazed windows in winter there are a number of methods to use from improving ventilation and reducing humidity, to professional inspection and maintenance.

What is Condensation?

Condensation on windows looks like water droplets or fog on the glass. It can be extreme with pools of water, one droplet, or a light haze on the window surface. When the cold surface of the glass connects with the warm air, it forms water. The water vapour in the humid air deposits itself on surfaces that are at lower temperatures. This is referred to as the ‘dew point’ which is the point at which condensation will occur. It is more likely to occur in winter when the air outside is much colder than the air inside the home.

Why is There Less Condensation on Double Glazed Windows?

Double glazing reduces the occurrence of condensation on windows because of how the windows are designed. Instead of using one pane of glass, double glazed windows use two layers of glass separated by an insulated layer which is usually filled with argon gas. The gap between the two layers of glass provides additional insulation. One of the advantages of this design is that it enhances the windows thermal performance and minimises the temperature difference between the interior and exterior glass, leading to less condensation.

Why do Some Double Glazed Windows Have Condensation?

While condensation is less likely, sometimes it can still occur on double glazed windows. In winter, the exterior window surface can become extremely cold and if that meets high warmth and humidity inside the home, condensation may form. Condensation can occur on the inside of double glazed windows if there is high indoor humidity, on the exterior if warm air hits the cold glass surface, or between the panes which indicates a potential problem.

Condensation on the outside window: Condensation on the outside window may appear as fogginess or water droplets and is a good sign if you have double glazed windows. This type of condensation shows that your double glazed windows are working to prevent the indoor heat from escaping. When condensation occurs on the exterior pane of glass, the interior pane of glass remains warmer which reduces the likelihood of condensation forming on the inside window.
Condensation on the interior window: Water droplets or moisture forming on the inside surface of the window tends to occur when there is a temperature change and extra heat or humidity is added to the room. Usually when this happens, there is too much humidity in the room and insufficient air circulation. You might see this in kitchens or bathrooms where there is more moisture in the air than other parts of the home. It is also more likely to occur in specific climate conditions like cold weather. While this type of condensation is unlikely to occur, it can lead to mould or mildew if it happens regularly.
Condensation between the panes: Condensation between the panes of glass in double glazed windows will probably look like a fog or steamy haze inside the window. When condensation is between the panes, it cannot be wiped away on the outside or inside. Unlike condensation on the outside or inside window, which is caused by simple temperature differences, this type of condensation indicates a fundamental issue with the seals. This breach allows moisture to seep in between the panes of glass into the air gap. When this occurs, the double glazed window will not be able to offer the same insulation benefits, and there is the possibility of mould growth within the window.

Solution for Stopping Condensation on Double Glazed Windows in Winter

The methods to stop condensation on double glazed windows in winter will depend on where the condensation is occurring. Condensation removal and prevention is very different when it forms on the outside and interior window surfaces compared to between the panes.

Removing Condensation on Double Glazed Windows

Removing condensation from outside windows: Condensation on outside windows is not harmful and actually shows that the double glazing system is working effectively. However, if you want to remove the condensation because you cannot see outside the window, there are methods you can use. Wipe the outside of the window with a dry cloth to remove excess moisture and create more air flow by opening the window.
Removing condensation from inside windows: To remove condensation buildup from window surfaces inside the home, wipe with a towel and remove any moisture that has accumulated at the bottom of the window. You can also use a hairdryer on a low setting to clear any mist or fog on the interior window.
Removing condensation from between the panes of glass: Because condensation inside the double glazed windows between the panes is usually a sign that the seal has broken, it is difficult to remove the moisture that has accumulated. The only permanent solution is to have the double glazed window repaired or replaced by a professional. There are some suggestions that you can remove the water by using WD-40, a hairdryer or leaf blower where the seal is broken to remove condensation. These are only possible if you can find the broken seal. It does not prevent it from occurring next time or fix the original problem.

Preventing Condensation on Double Glazed Windows

Preventing condensation on outside windows: To prevent condensation building up on the outside window surfaces, increase the amount of shade you have in the area outside. When windows have shade they can retain more warmth which makes the window surface less cold and reduces the likelihood of condensation appearing. Plant shrubs, bushes or trees to create shade or utilise structures like pergolas or wind sails that protect the window from cold air. They allow the window to warm up so that evaporation happens quickly and reduces condensation buildup.
Preventing condensation on inside windows: There are a number of ways to prevent condensation building up on the interior surface of double glazed windows. Improving ventilation in the home is crucial for reducing condensation. Ventilation can be improved by simple steps like opening a window, or using ceiling or exhaust fans to help circulate the air particularly when cooking or showering. If using a clothes tumble dryer, make sure the room is well ventilated by keeping doors and windows open to avoid moisture build up. Keep curtains and blinds open to allow air circulation around the window. If your home is humid, dehumidifiers and moisture absorbers are ideal to help combat condensation. Humidifiers remove moisture from the air, while moisture absorbers like silica gel help absorb moisture in different areas of the home.
Preventing condensation between window panes: Preventing condensation forming between the panes of glass in a double glazed window is difficult. When condensation occurs between the panes of glass, it is usually a fault with the window which requires a professional to fix it. The only way to prevent condensation from forming inside your double glazed windows is to make sure you use specialists for supply and installation of your windows. A poorly installed window may lead to issues like leaks that cause condensation. Professional installers understand building codes and regulations and make sure the installation is not only legal, but will work at optimum efficiency. An expert will know how to measure the window correctly, properly align the frames, create the right airtight seal and fit the sealed glass for maximum performance and longevity. Professional installation will eliminate the likelihood of structural issues occurring and is the most successful way to avoid condensation.

One of the many benefits of double glazing is the reduction of condensation compared to single glazed windows. The two panes of glass with a gas filled vacuum seal in between provide a thermal barrier that reduces moisture buildup. However, while this innovative technology is a great solution to fight moisture and condensation, it may occasionally occur, particularly in Winter. The most effective way to reduce the possibility of condensation is by using professionals like Windows for Life, experts in all aspects of double glazing.