Electric water heaters use electricity to heat water. They do this primarily by way of an immersion heating element that can heat the water to a temperature adjustable by the user.
Electricity is safely converted to heat the water by way of an element. Electricity flows through an inner wire in the element, which is covered in filler material and an outside sheath. These conduct heat from resistance but not electricity.
An electric water heater has either one or two heating elements immersed directly in the water. In systems with two elements, the upper element is the first to engage when power is turned on and heats the water in the upper third of the tank for immediate use. As hot water is drawn from the top of the tank, a dip tube moves cold water to the bottom. Once the upper third is heated to the specified temperature, the lower element activates and heats the rest of the water. A water heater with only one element has it located at the bottom, which requires a longer wait for hot water to move to taps.
Modern water heaters may also have smart technology that prevents elements from engaging when no water is present or pouring out.