It’s more efficient to leave a room at a constant temperature than turning the heat down overnight (or when you’re not home)
It takes less energy to warm up a cold room in the morning than it does to maintain a constant temperature throughout the night. If you have baseboard heaters, know that they supply heat to each room individually. If you have thermostats in separate rooms, you can use the concept of “zones” to heat certain areas of your home more than others, which saves up to 20% in heating usage compared to heating both occupied and unoccupied areas. Be sure not to vary the temperature between rooms by more than 2C.
Look through your house at the beginning and end of the day to make certain your heat use matches your room use. Close doors to rarely occupied rooms and areas.