October - time for external condensation

View from front bedroom

Shortly after having our new windows installed we noticed that we were having condensation problems. Unlike older inefficient windows the condensation was forming on the external / outside face of the window where it might previously have formed on the internal / inside face of the window (and been easier to clean off or control with suitable ventilation).

Internet searches lead me to an article by the Renegade Conservatory Guy so we are not alone in having this issue with our new windows. I agree with most of the comments which he makes and understand that it 'proves' that the windows are being efficient. Something that appears to have been forgotten is the fundamental reason for having a window. A window is a break in a wall offering access to external light and views.

View from lounge window

For me my new windows; especially the westward facing ones; often appear to be opaque on an autumnal morning and can stay this way into the afternoon. Fundamentally they do not function appropriately as windows. A bit like selling an energy efficient oven which doesn't function in winter when there is an ambient temperature below 20 °C!

There is an interesting, although fairly technical, document available from Saint Gobain Glass available directly as a PDF or via their web page. Some others are comparing the issue with having snow on the roof after fitting loft insulation and I couldn't disagree more strongly with this analogy. Windows are not there to be energy efficient - a brick solid wall is more efficient at keeping the heat in - they are there to see out of!

View from kitchen window

So before you rush out and buy 'A' rated windows consider your favourite outlook from your house and how much you enjoy gazing out on a crisp autumn morning watching the leaves falling from the trees. Now consider replacing your windows, spending £000's of pounds on the replacements and losing your view. Will you be happy knowing that you will be saving less than £150 a year on your gas bill and 0.76 tonnes of CO2?*

Other consumer issues / environmental blogs:

Highly efficient gas fires

Cavity wall insulation
Environmental home improvement consumer

*Calculation based on the Glass and Glazing Federation online calculator for a detached house replacing timber double glazed units with A rated windows.