A tank water heater is a common appliance used to heat and store water for residential and commercial use. It consists of a large insulated tank that holds a specific volume of water, typically ranging from 20 to 80 gallons. The heater uses either electricity or gas to warm the water, which is then delivered to faucets, showers, and appliances when needed. These heaters operate by continuously heating the water in the tank to a set temperature, ensuring a ready supply. While they provide a reliable source of hot water, they can be less energy-efficient compared to tankless water heaters, which heat water on demand.