This contribution presents a concept for the direct integration of a refrigerant/water Heat Exchanger (HEX) with a Phase Change Material (PCM) in the hot superheated section of an R32 - air source compression Heat Pump (HP) cycle, for optimized Domestic Hot Water (DHW) generation in multi-family houses. The concept takes advantage of the PCMs high thermal storage capacity integrated into a high performance compact enhanced plate-and-fin aluminium HEX. On the refrigerant side, it works as a de-superheater for DHW generation during heating and cooling operation whereas the process water is connected to decentralized DHW storages located in single apartments of a low energy building. We present results from simulations at a system level for typical operating conditions and corresponding seasonal and annual performances. Compared to conventional systems, the results indicate savings up to 11% of electric energy over the year for DHW generation in average climate.