To reduce window condensation in the home, keep the humidity at a reasonable level, install storm windows and run ventilating fans as long as possible. Keep the fireplace damper open to let moisture in the air escape more quickly.
Condensation on the windows is from excess moisture in the air. This is often due to high levels of humidity. Use a dehumidifier in the home, and turn off the furnace humidifier. Ventilate the home, and keep windows and doors open whenever possible. After using a bathroom, kitchen or laundry room, air it out by opening a window or door. A more expensive option is to have double or triple-glazed windows installed.