In most cases, water is heated in utilizer due to the products of combustion. It will later be used for recharge. In this case, preheating can reduce the consumption of fuel used for heating-up or evaporation by supplying liquid with a higher initial temperature to the boiler. Also, in some cases, the heated liquid can be supplied for space heating or used for other industrial needs. This allows the company to save a large number of resources, both production and financial.