It is a common assumption that condensation forming on your window is an indicator that something has gone wrong.
Actually, it can be the opposite. Condensation appears when vapour in the air hits a cooler surface, such as a mirror, tile or window.
Droplets appearing on the external pane of your window means that it is performing as it should – keeping cold air and moisture out and the warm air in. Only if condensation begins to form between the panes of glass in your window should you be concerned.