A domestic electric heater is used to heat water to a temperature higher than the atmospheric temperature.
It is usually in a cylindrical shape and fixed to walls or flooring. It has a capacity of about 100 litres to 150 litres. It consists of an electric conductor having a high resistance. When current passes through it, it is heated by the dissipation of electrical energy through the resistor. It could be generally around 2 k watt to 3 kilo watt. The wattage and capacity depend on the particular heater.
As the water is heated using convection of heat, the temperature of water raises. There is a thermostat device, which measures the temperature and shuts the heater off, if it is more than a predefined value.
To protect the heat energy from being lost, an thermally insulating container is used for the water tank. to protect the users from electric shocks, the container is usually made of an insulating material. The heaters have usually a long life period of 20 years or more.