HYBUILD will develop two innovative hybrid storage concepts: one for the Mediterranean climate primarily meant for cooling energy provision, and one for the Continental climate primarily meant for heating and DHW production. HYBUILD action is a systematic approach for developing operationally integrated thermal and electric components and systems from TRL4 to TRL6 and beyond. The hybrid storage concepts are based on: a compact sorption storage, based on a patented way to integrate an innovative adsorbent material within an efficient high surface heat exchanger, a high density latent storage, based on a high performance aluminum micro-channel heat exchanger with additional PCM layers, and an efficient electric storage. The balancing of thermal and electrical energy flows will be realized by seamless integration of electric building components in a DC coupled system and by efficient conversion and upgrading of electric surplus and renewable thermal energy sources by compression and adsorption heat pumps. The components will be integrated to realize the full-scale hybrid storages (with overall volume between 1 and 2 m3), which will be properly managed by advanced control and building energy management systems (BEMS), able to optimize the interactions between components and district network. Such a configuration will allow reaching energy savings ranging between 20 and 40%, on yearly basis, both in Mediterranean and Continental climate for non-connected and district-connected buildings. HYBUILD hybrid storages will be used to upgrade existing building configurations and monitored in three different demo sites in near-life operation, both for non-connected and district-connected buildings in different climates.