Condensation on one double glazed window - advice please

[missminimum]

I would appreciate advice on what could be causing the condensation on my daughter's bedroom window. All of our house has double glazed windows of different ages, this window is one of the old ones. It is a bay window and the curtains have blackout linings. My daughter feels the cold and does not like to have the windows open. There are no small windows just two large panes that can be opened. She also keeps the curtains shut a lot, but the windows are streaming with condensation every morning. This has led to some mould around the window edges. We think it could be due to the age of the window, as no other windows in the house have this issue, but before we go to the expense of replacing it, would appreciate your opinions please. Many thanks

Do the newer windows have trickle vents? Ventilation is the only answer really. If she doesn't want to open the window then you will need get a towel and dry the window off every morning.

Thanks Catchyjem. The new ones don't have trickle vents, may need to think of replacing it and having vents

Is it all on the window itself or is it within the space between the inner and outer panes?

If it is inside the window, then I used Cloudy2Clear and they sorted it very quickly and for a very reasonable price.

Mischance it is not between the inner and outer panes, it is on the inside of the window if that makes sense. Thanks