First it's normal to see a SMALL amount of condensation (usually in the
corners of the windows) overnight. You however, have a little too much
moisture in the air (windows are fine.)

As others have pointed out, either turn down the humidifier during cold
weather and use the kitchen fans when cooking and bath fans when bathing in
the winter. (What you see on the windows is also being seen in the attic
cavity and inside the walls as condensation when the moisture hits the dew
point inside the insulation.)

Dennis

wrote in message
oups.com...
I had some double glazing fitted last year, it was fitted by a FENSA
We are happy with the windows etc, but in winter sometimes get
condensation on the windows. This only happens on mornings where it is
particually cold and wet out, it burns off by midday, and is worse in
rooms where people have been sleeping.