In a video that details how a hot water heater works, you will find that the tank works non-stop to provide water to the home. The tank can be powered by gas or electricity, which is used to produce the power needed to make the heating mechanism work. The tank itself is insulated to help keep the heat from escaping and allow the water to cool.
Inside the tank sits a thermostat that tells the heating mechanism when to activate and when to shut down within the hot water heater.
Once the desired temperature has been reached, the water is ready for distribution throughout the home. Once you turn on a hot water faucet, the heated water flows from the top of the tank throughout your home. The heated water is then replaced by cold water at the bottom of the tank, heated by the heating mechanism located at the base of the tank. The hot water heater tank is always full of water kept at a constant temperature for use within your home.