To support New York City’s ambitious clean energy goals, a battery of new technologies will be needed. Once such technology is a wastewater energy transfer (“WET”) system, which pulls thermal energy from wastewater lines (e.g., sinks, showers, toilets, etc.) for reuse in the heating, cooling, and domestic hot water (DHW) systems. WET systems are especially important technology as they can be used initially for DHW production and then as an enabling step to reduce heating/cooling loads for the later heat pump systems. Engineering studies show the combination of a WET system and heat pumps will prove to be a technology that will result in both immediate and future energy and carbon savings. It not only effectively reduces carbon emission immediately but also lowers the barrier to entry for electrification. Moreover, a WET system can be widely duplicated in apartment complexes and high rises regardless of project sequencing for benefits so is poised to be widely replicable throughout New York.