Integrated HVAC and plumbing system for a 3-apartment house using a Panasonic Aquarea T-CAP 12 kW air-to-water heat pump as the primary energy source. The heat pump feeds a buffer tank and hydraulic separator that distributes hot water through three independent circuits: domestic hot water (DHW) with three 200–300 L tanks and recirculation pump, fan coil cooling units for each apartment floor, and a swimming pool heat exchanger loop. Each circuit has its own circulation pump (P1, P2, P3) and manifold for independent flow control and temperature management. This architecture ensures reliable, zone-controlled comfort while optimizing energy efficiency across heating, cooling, and DHW demands. Fork this diagram on Diagrams.so to customize tank sizes, pump capacities, or add additional circuits for your specific multi-unit project. The modular design allows easy scaling to larger buildings or alternative heat sources.