Please call today to make
an appointment:  01782698040

Window Condensation - Why It Happens And How To Cure It

example of window condensation problem

During particular months of the year, window condensation becomes a problem and a worry for people around the country. Fortunately, we have put together a comprehensive guide to where it comes from, why it happens, and how to get rid of it!

What is condensation?

Condensation occurs when the temperature of a gas or vapour drops below its dew point, causing it to turn into a liquid. A perfect example of this is the liquid morning dew you see on your grass in the morning after a colder night. Condensation is also why you can see your breath when it's cold, due to the differing temperature in your mouth and the outside air.

Why does condensation appear on our windows?

Condensation appears on your windows when the vapour inside your house is not allowed to escape during the colder months. This water vapour builds up in the air and eventually turns to water when no more can be held. The vapour often liquifies on the coldest surfaces in the house, which happens to include your glass windows. At first, you will notice a light mist on the glass, but that will often turn to water droplets if it is not dealt with. Modern homes were well insulated to keep the warmth in during the winter months, but that also increases condensation due to the lack of ventilation. It is also worth noting that condensation is not isolated to inside the home, you can also get external condensation. This is often seen in spring or autumn when the glass falls below dew point, and the air is humid.

Is condensation on windows bad?

Condensation is common and natural. At first, misty windows may seem nothing more than a slight irritation, but that can quickly escalate. Unfortunately, if left untreated, condensation can lead to mould, damage to walls, and damage to soft furnishings. Black mould can even cause respiratory problems, so condensation is definitely an issue to be taken seriously. Fortunately, external condensation is unlikely to cause damage.

Does the window type or design impact condensation?

Window design and technology is always moving forward to create more energy-efficient options; however, this does not always have a positive effect on condensation.

Single glazed windows – These provide the biggest internal condensation risk. The single glass pane does not heat up with the room and remains cold from the outside air, thus producing condensation rather efficiently.

Double glazing (less energy-efficient options) – Rather strangely, double glazing that is less efficient in saving energy is actually more efficient in reducing condensation. The internal glass pane is heated by the room and some of this heat also warms the external pain, thus reducing the risk of both internal and external condensation.

Double/Triple glazing (energy-efficient) – Unfortunately, the more energy-efficient the double or triple glazing is, the higher the risk of external condensation. The internal glass pane will heat with the room, so internal condensation isn’t much of a worry, but little heat will reach the external glass pain so external condensation remains likely when it is cold outside.

How to prevent window condensation

Keep rooms well ventilated – Keep your rooms well ventilated by opening windows or using trickle vents in order to cut down on internal condensation. In rooms where steam is produced, such as the bathroom and kitchen, ensure that ventilation is provided via open windows or extractor fans. When drying clothes, try to hang them outside when possible or invest in a dehumidifier.

Replace single glazing – The biggest cause of internal condensation on windows is single glazing, so replacing it with double or triple glazing can go a long way to solving your issue. This will also keep your rooms warmer and could save you money.

Keep your home warm – The warmer your home, the more water can be retained in the air and the less will condensate on the windows. However, you still need to keep the rooms well ventilated too. Radiators under the windows are a great way to keep them warm and cut down on condensation.

Unoccupied rooms – Condensation is common in occupied rooms, especially if the heating is turned off and the door is kept shut. The only place for the water vapour to go is the cold windows. If possible, keep the door open, the room ventilated, and the heating switched on in unoccupied rooms.

External condensation – There is not much you can do about this unless you can control the weather. It should only last for a couple of hours until the wind or sun dries it anyway. Certain glass can reduce condensation on conservatories.

Condensation between window panes – Double and triple glazing should be sealed to prevent this from happening, so if you notice it, you may have a problem with the seal, and it should be replaced. Condensation can occur in the cavity if you have secondary glazing beside single glazed windows.

Improve your home with our doors and windows

Contact us now to schedule a free consultation