Heat

I am looking for a way to heat part of the house. Kind of like the english way of wintering. Heating only the rooms that my daughters and wife sleep in. There are many ways to do this but there are only a few that could save me money. What I am thinking is about is getting an electric heater that could keep their rooms warm but the rest of the house would stay at about 50 or 65. During the day running the heat enough to keep the chill out of the air. During the night keeping their room with the heater.