Why do my double glazed windows fail/blow & steam up?
We get asked this question all the time, "What causes my windows to steam up?". The reason double glazed units fail is down to something called, solar pumping. Solar pumping is used to describe the movement that takes place in a double glazed unit from the change in weather conditions. As the temperature increases during the day the unit heats up and expands and when the temperature decreases the unit cools down and contracts. This process is called solar pumping and over a period of years is enough movement to break the seal and cause condensation to build up inside the unit. Conservatories and windows facing the sun are notoriously bad for failing due to the excessive change in temperature between day and night.
The rubber seals have shrunk, does this cause the double glazing to fail?
The simple answer is no. This is a very common misconception, although they can be unsightly they really don't contribute at all to the break down of a double glazed unit. The reason for double glazed units failing has been outlined above. The purpose of rubber seals, known as gaskets, are to hold the double glazed unit in place, help prevent draughts and excess water from getting into your frames. All uPVC window frames tend to be designed with drainage holes and therefore any excess water that may enter the frame due to shrunken gaskets should drain away and not cause any issues.
Why do my windows stream with condensation?
Condensation can take many forms when it comes to double glazing. As covered in the first answer condensation forms between the glass when the seal joining the two panes of glass breaks down, allowing fresh air and moisture to build up. There are lots of people who's double glazing has not blown, but suffer from excessive internal condensation on their windows, creating lots of unwanted mopping up in the mornings. This is a very common problem in winter time and especially living in the damp climate of the south west. It occurs due to a number of reasons, but essentially is a result of heat loss through the glass causing moisture in the air to condense when it comes in contact with the cold surface of the glass. The extent of the condensation can vary due to a number of factors such as humidity of a building and ventilation. If you click HERE there is all the information that you need with regards to what causes internal condensation, what can be done to tackle the problem and why with newer, more efficient glazing we sometimes see condensation form on the outside of the glass.