The ShowPass project, located in Barcelona, exemplifies how energy efficiency solutions can be applied to the retrofit of existing housing in dense urban environments. The intervention is based on the EnerPhit-Plus standard and achieves a primary energy demand of just 4 kWhpe/m²·year, thanks to a smart combination of passive measures, active systems, and advanced energy management.

Insulation has been installed internally to preserve the urban aesthetic, using mineral calcium silicate, which is highly resistant to humidity. The thermal envelope achieves a U-value of 0.60 W/m²·K, and the building’s airtightness is notable, contributing to stable and quiet thermal comfort. Ventilation is provided by a Passivhaus-certified compact unit that integrates mechanical double-flow ventilation, heating, and cooling.

An aerothermal heat pump has been installed for domestic hot water, operating with a passive solar evaporator—requiring no electrical connection and producing no noise. Climate control is supported by a VRV (Variable Refrigerant Volume) system, and the entire setup is managed by a Loxone-Modbus smart system, which optimises energy use based on weather forecasts and user preferences.

Renewable generation is achieved through two photovoltaic systems: a 1.6 kWp monocrystalline array and a 1.0 kWp CIGS system mounted directly on the roof without a substructure. Although roof space limits total capacity, the systems cover 34% of the building’s energy consumption.

Additional measures include shower heat recovery, water consumption sensors, and recycled materials used in insulation and furniture. These strategies have enabled the building to be certified as CO₂-neutral, with over 90% emissions reduction across its lifecycle.

Key figures:

• Building condition: Renovation
• Building type: Terraced individual housing
• Construction year: 1900
• Primary energy consumption: 4 kWhpe/m²·year
• Energy performance certificate rating: A
• Renewables: Solar photovoltaic, energy recovery from waste, heat pump