The electric water heater operates using electrical energy, where the resistance inside the water heater is heated and thus the water is warmed.
On the other hand, the electric boiler, in addition to heating the water through electrical energy, has an internal heat exchanger (coil) with the ability to connect to the central heating system, to assist in the production of hot water. This limits the use of electrical energy.
This means that once connected, the hot water produced, for example, by the oil boiler, heats not only the heating bodies but also the water in the water heater, thus promoting savings during the winter months.