Using the heat of condensate after the economizer, the heating system water of high temperature is heated Example: Heat source: condensate with a temperature of 40 C, flow rate ~ 20 m3 / h Medium to be heated: network water with a temperature of 55 C Thermal power 180 kW * h, efficiency factor ~ 4.75 , electricity consumption ~ 38 kWh (180 ÷ 4.75) An electric heat pump is 5 times more efficient than an electric boiler !!! With the selling price of heat 3.83 Euro cents / kWh, and the price of electricity 5 Euro cents / kWh, the project payback period is ~ 4 years.