"Building efficiently does not mean sacrificing quality: it means integrating quality into the building envelope itself."
Energy-efficient construction in the Barcelona metropolitan area presents very different challenges depending on location. Sant Cugat del Vallès, with winter temperatures that can reach -5°C and summers exceeding 38°C, demands a thermal envelope radically different from that of Premià de Mar, where marine humidity is the primary limiting factor.
1. Thermal envelope in Sant Cugat: full insulation
The Sant Cugat home was built with a ventilated facade system with a total thickness of 36 cm: 20 cm concrete block + 12 cm extruded polystyrene insulation + 4 cm ventilated air gap + natural stone cladding. The resulting thermal transmittance is U = 0.18 W/m²K, well below the CTE limit for climate zone C2 of Sant Cugat (U ≤ 0.34 W/m²K).
2. Maresme envelope: moisture control
At Premià de Mar, the priority is condensation moisture control. The facade uses an ETICS system (External Thermal Insulation Composite System) with 10 cm expanded polystyrene and a textured mineral mortar finish. A vapour control layer on the warm side of the insulation is essential to prevent interstitial condensation during cold months.
3. Heat pump and KNX home automation
Both homes incorporate air-to-water heat pump systems with underfloor heating and fan coil distribution. The seasonal coefficient of performance (SCOP) is 3.9 in Sant Cugat and 4.2 in Premià, thanks to the slightly milder coastal temperatures. KNX home automation manages lighting, HVAC, blinds and the security system from a unified interface.
Conclusion
Both projects achieved Energy Rating A — the highest possible. Non-renewable primary energy consumption is below 25 kWh/m²year in both cases, thanks to the combination of an optimised envelope, heat pump and 6 kWp photovoltaic installation. Discuss your project with Nosolo Design.