A cold snap could freeze your pipes. Let household activities such as cooking, laundry and bathing help heat your home and add moisture to the air. Use exhaust fans sparingly. Electric space heaters are efficient only for heating one room. If you use a space heater, turn the central thermostat way down and close off the room with the heater.
People generate heat.
If you have any guests, lower the thermostat a few degrees before they arrive. Leave shades and draperies open on sunny days and allow the sun to help heat your rooms. Remember to close them at night Close the fireplace damper when the fireplace is not in use. Add glass fireplace doors to reduce heat loss up the chimney, even when the fireplace is in use. Make sure registers for supply and return air are not blocked by draperies or furniture.