Modern boilers are omnivorous, that is, they can work on any type of fuel — from diesel fuel to natural gas. Depending on the cost of resources and their availability, for example, in some regions, a restriction on electricity consumption may be introduced when the householder chooses the method of heating water. But most include the use of combined boilers, which can work both from gas and from electricity. For example, in the case of gas interruptions, an electrical water heating system automatically turns on.