17 Signs You're Working With Misted Up Double Glazed Unit Why is My Double Glazed Unit Misting Up?

If condensation develops on the outside of double glazing it is not a problem and in fact, it is a sign that your windows are functioning correctly and keeping heat in your home. If it appears on the inside of window panes it's a sign of an issue.

If you see moisture trapped between your windows, it indicates that the seals are failing. This can lead to higher heating bills and lower insulation. This can be caused by a variety of reasons.

1. Faulty Seals

Condensation that is able to get into the the glass panes is usually the reason for misting on the outside. The condensation usually appears as a cloudy layer and reduces the transparency of your window. The misting in double-glazed windows is more serious and indicates that the seals on the insulating unit are not working properly.

This indicates that the seal has failed and water is leaking between the two panes of glass. This causes the fogging, and reduces the efficiency of your window. Double glazing that is not functioning properly can impact the overall appearance of your home as well as the safety of your family.

There are many reasons why your double-glazed units could fail, such as wear and tear from natural aging, a faulty installation or issues with the design of your window frame. It is crucial to choose a reliable installer who is able to guarantee their work and will not make any warranty claims against the manufacturer.

One of the primary reasons why your double-glazed units could fail is because they've become damaged by water. This could be the result of poor installation or maybe a lack of drainage or spacer blocks. The moisture will then seep into the seals, causing them to break over time. This can lead to condensation between the glass panes.

Another common reason for a failing double glazed unit is that the desiccant in the unit is saturated. The desiccant is designed in order to absorb excess moisture, thus preventing it from getting into the space between the glass panes. However, as it becomes over saturated the desiccant will start to lose its ability to absorb water and eventually the moisture between the glass will increase, causing the mist that is frequently seen.

A swell of moisture forming between the strip of aluminium and the seal is usually the first sign. It is important to remember that this is not a quick fix, and the best option is to replace the entire unit. A hairdryer that is used regularly is a great method to remove condensation build up from your windows and can be particularly efficient in areas with high levels of humidity and condensation. A dehumidifier is an excellent option to add to your home to stop the build-up of moisture and keep it draught-free.

2. Poor Ventilation

Condensation may form on double-glazed windows due to various reasons. Condensation that is visible on the outside of windows is typically a positive sign, as it indicates that your windows are working well and keeping warm air inside and cold air out.

If the condensation is inside your window, this could indicate an issue. This is because the condensation that forms inside your window is a sign that the seals have failed and water could get inside the glass panes.

This is typically due to inadequate ventilation. If there is no air circulation the warmth inside your home is held in and this causes moisture to build up. This is particularly prevalent in kitchens and bathrooms where there's an abundance of moisture and humidity in the air. If you have a misty double glazed window, it's important to examine your ventilation and decrease any excess humidity in the room to stop condensation from forming.

A failure to seal double glazing can cause an increase in energy bills. misted double glazing repairs near me is because heating systems will have to perform more efficiently to keep your home warm. This could add up. Double glazing that leaks could allow cold air into your home and make it feel colder.

It's important to check your double-glazed windows frequently to ensure that the seals remain intact. If you regularly clean your windows using an organic cleaning agent and don't let them be too wet, the seals are likely to last for a long time.


If you notice that a mist is forming on the double-glazed unit, it may be time to replace it. The good thing is that if make the right choices, you can replace your current double glazing at less than the cost of a new window. It's important to note that this is not always the best option when your frame could not support a new double glazed unit and in this case, it's usually necessary to have an entire new window constructed.

3. Installation error

If your double-glazed windows have been installed recently and is already beginning to cloud up, it could be due to poor installation. It is crucial to choose an FENSA regulated installer to ensure your windows comply with UK building regulations. A poor installation could cause the window seals to fail, which could result in moisture between the panes. This will then eventually corrode the spacer bar made of aluminium and lead to the sealant inside the unit degrading. This can cause the anti-moisture granules within the spacer bar to be saturated with moisture and will no longer function as effectively as they ought to.

If you notice condensation on the side facing your room, it means that there is a problem with ventilation in that space or property. It could be a mix of both and it's perfectly normal for double glazed units to have some condensation on the outside, especially if you are using a sealed unit with high-quality Argon fill. However, this will disappear as the glass gets warmer and air temperatures increase.

On the other hand, if you have condensation between the window panes, then there is a flaw in the window and it must be replaced. Faulty double glazed windows no longer insulate your home as well as they should, leading to higher energy bills and possibly damaging the window frame.

It can be a bit of a hassle to need to replace your double-glazed windows, but it is something which must be taken care of when you notice the signs of the sealant failing. It is recommended to carry the replacement out in the summer, before winter sets in so that you can benefit from the improved thermal efficiency of your double-glazed windows.

Double-glazed windows should last between 10 to 35 years. However, a number of reasons can cause them to break earlier than this. A leaky seal let moisture into the window, which can cause it to fog or cloud up. This can be caused by any number of things including:

4. Age

Double glazed units are a powerful and airtight way of keep your home warm and prevent condensation. The secret lies in the space between the two panes of glass which is sealed under conditions of vacuum using dehydrated gas or inert gas and secured by secondary and primary seals. This greatly reduces heat loss and keeps the inside of your property warmer whilst decreasing energy bills.

Over time, due to normal wear and tear, the seals on your double glazing may deteriorate and allow moisture to enter the space between the window panes. This is caused by various weather conditions, for instance, when temperatures rise and fall the gases within the units expand and contract, over time, this causes the seal to break down allowing moisture to get in.

It's important to remember that windows that are misty don't just affect the aesthetic of your home, they also decrease visibility and may cause the growth of mould or mildew If left unchecked. This can be harmful to your health and could cause damage to the frame of your windows.

It's time to replace your double-glazed windows if you notice that they are becoming more steamed or misty. A broken window is not just ugly but also allow cold air to enter your home and increase your energy costs.

Older double glazing doesn't provide the same insulation as newer models, meaning they let more noise in, which could adversely affect your quality of life especially when you live near the busy highway or railway line. Double-glazed windows are designed to keep the noise out whilst keeping the heat in, helping to improve the comfort of your home and wellbeing.

Windows that are misted are a typical issue that can be easily solved by a professional double glazing company. It's important to check whether your window is covered by warranty before repairing or replaced, based on the severity of the problem you may be able replace the glass unit rather than replacing the entire frame.