Although there are two types of water heaters--storage tank and on-demand water heaters--the chances are good that you have the conventional storage type of heater.

On-demand water heaters are efficient and economical because they do not store and continually heat water but heat it as it is required.

Because they are less common, it is better to leave their installation and maintenance to people who know what they are doing.

Both gas and electric water heaters operate in similar ways: when you turn on a hot water faucet or use hot water in a dish or clothes washer, water pipes draw hot water from the tank.

The heated water is drawn from the top of the tank and is replaced by cold water that is carried to the bottom by a dip tube.

When the thermostat signals that the water temperature has dropped, a burner in a gas heater or a heating element in an electric heater starts up to heat the water.

Set the temperature control to about 150 degrees F or lower if you have no dishwasher or if you have small children or elderly people in the home who might scald themselves.

To maximize your water-heating energy, it's a good idea to insulate your water pipes if they run a long way from your heater to faucets.