Every day, a tremendous amount of warm water is used once before ultimately being discarded down the drain. In fact, the United States Department of Energy estimates that the equivalent of 350 billion kilowatt-hours of hot water, is lost down the drain every year in the U.S. alone. Wastewater provides the ultimate renewable energy source, with an inexhaustible supply of thermal energy. Wastewater heat recovery is a process that can recover the heat energy from all that hot water and use it to heat buildings, cool them, and heat the domestic hot water supply. One of the easiest and most effective ways to decarbonize a multi-family building is to recycle the energy in the wastewater! Domestic hot water is the largest rogue load in the building. Electrification of DHW non heat pump systems can cost much more, require higher electrical service, and cause large energy bills for homeowners. By using a high efficiency waste heat recovery heat pump to produce hot water you can eliminate carbon, reduce operating costs, and allow for peak avoidance of electrical use.