We have just received a great flyer from Fensa, reminding us about condensation and the questions we will be asked at this time of year. It is something we have written about before, but if this is any help to our customers, then any information is always great!

“We’re now well and truly into Autumn: the leaves are falling, temperatures are dropping and the heating’s on.

For installers this typically means the same questions from homeowners about window condensation.

My windows are all misted up outside. What’s wrong with them?

Here at FENSA we regularly arrive at early assessments in Autumn to be greeted by a window covered in external condensation and most of the time the customer wants to know exactly what is wrong with their new windows.

The simple answer is nothing is wrong with them. In fact it’s proof they’re doing their job.

If nothing is wrong, why is there condensation?

The longer answer is that the windows the FENSA community install these days are so much more thermally efficient, that the heat we use to warm our homes doesn’t make it through to the outer pane.

This pane of glass is therefore colder and when its temperature is below dew point moisture in the air condenses on it.

Why does condensation only form at certain times of year?

The reason it is worse in Autumn (and Spring) mornings is that the temperature of the glass can really drop overnight but the dew point can still remain fairly high.

Some windows can be affected more than others and slight changes in orientation or shelter can mean that windows or even panes next to each other can react differently.

What can I do to stop condensation forming?

Unfortunately there is not much we can do to stop this phenomenon. It usually doesn’t last long and shows that the heat being used to warm a home is being saved, thus potentially lowering heating bills and carbon emissions.”