That is Mary's question. With utility prices shooting up, she wants to know if gas heat is less expensive than electric and if it is cheaper to heat the whole house with the central system or to use space heaters.
Gas produces cheaper heat.
As a rule, it is cheaper to heat a home with space heaters, as it is cheaper to cool a house with window units rather than using a central system when you want to heat or cool only the rooms you are using. There are zoned central systems, which do the same thing to a certain extent. Manually closing central-system room vents can lead to equipment problems and may not affect operating cost, since most systems still run full blast. Closing the door to unused rooms isolates their temperature from the thermostat. When closing off rooms, just close the door, don't seal it in any way or put a towel to block the gap under the floor.