ᐅ Windows fog up, with high humidity causing mold growth on the window sills.

We have a problem with the windows in our single-family house. Since the cold season started, every morning our windows are completely fogged up. These are standard double-glazed uPVC windows. We ventilate and heat regularly, and a humidity measurement showed values between 45 and 55%. Room temperatures range from 19 to 22 degrees Celsius (66 to 72°F). In my opinion, these are normal values. What can I do to prevent the windows from fogging up? Sometimes the condensation is so severe that water drips from the panes and mold forms in the corners of the window sills.