The Migros shopping mall, located in the heart of Lugano, is a multifunctional building with multi-level commercial space, self-service restaurant, training rooms (Migros School Club), fitness center and multi-storey underground car park. The building from the 70s needed a complete renovation. Lombardi Ltd. was charged with the design services (Ph. 32 due diligence + Ph. 41 tender phase + Ph. 51 execution phase) of the new heating and cooling system, the air conditioning, the sanitary and sewage system (waste water and rain water) and the renewal of the fire extinguishing system (sprinkler system). Great attention was given to user needs in terms of functionality, comfort (thermo-hygrometric conditions, acoustic effects of the installations) as well as energy consumption and environmental sustainability. The energy for heating, air conditioning and domestic hot water is generated by heat pumps supplied with industrial water. The production of domestic hot water also uses the waste heat from the cooling of the refrigerators of the cooling chambers. The hot water for the fitness center is produced by a gas boiler. A mixed system (ventilation + fan coil) ensures compliance with the required conditions and allows for a high level of system flexibility. Air treatment units with heat recovery ensure high indoor air quality and reduce energy consumption. The rehabilitation of building and technology while maintaining the shopping center in operation was a major challenge and was resolved through disciplined planning, organization and management (installation of the new system in parallel with the operation and dismantling of the existing system). The works were successfully completed, and the safety of the users was ensured at all times by carefully defining timing and logistics and coordinating the collaboration of the various professionals.