Wastewater leaves the home at an average temperature of 27 degrees Celsius. Cooling that water down to 2 degrees recovers heat that can be reused directly in the house — worth 39 kton CO₂-eq of reduction per year in the ambitious scenario for 2030.
Heat loss through the sewer is one of the last untapped heat leaks of a home. Recovery makes the heat supply circular, without any loss of comfort for the resident.