Why have i got Heavy condensation on new double glazed windows?

A few wild guesse here- You have floor length curtains in front of the Windows that block the heat of the room from flowing onto the glass. You have high humidity in the home during cold weather. Your humidifier/humidistat is malfunctioning causing excessive moisture in the furnace ducts. The people downstairs are constantly cooking vats of chili. The Windows are left open during the night. The kids leave the steam room doors open. Solution- correct the humidity level in the air, whether from cooking, or humidifiers. Allow heat to pass around the glass, evaporating the condensation or frost. If neither is feasible, make sure paint on walls is water resistant.