External Wall Systems in Passive House Standard: Material, Thermal and Environmental LCA Analysis

The construction sector, a significant consumer of energy, possesses the potential to realize substantial environmental and economic advantages through the adoption of innovative technologies and design approaches. Notably, the Passive House standard, exemplified by energy-efficient single-family homes, emerges as a prominent solution. This study analyzes five external wall systems across multiple stages: (i) a literature review and examination of external wall techniques within the passive standard, utilizing the Passive House Database; (ii) a material and technological assessment of three wood-based and two masonry constructions; (iii) an in-depth thermal performance analysis of selected external partitions; and (iv) a Life Cycle Assessment (LCA) of the external wall systems. Our findings indicate that among the single-family homes built to the passive standard, 50.94% utilized timber constructions, while 34.21% employed masonry. Thermal analysis revealed that the masonry wall, EW-M-01, exhibited superior thermal efficiency with a heat transfer coefficient (U-value) of 0.0889 W/m2K. Meanwhile, the wooden wall, EW-T-01, led its category with a U-value of 0.1000 W/m2K. The LCA highlighted that the wooden wall EW-T-02 presented the lowest integrated non-renewable energy demand (PENTR) at 425.70 MJ/kg and the most favorable Global Warming Potential (GWP), with a reduction of 55.51 kg CO2e. Conversely, the masonry wall EW-M-01 recorded the highest energy demand and CO2e emissions, at 780.96 MJ/kg and 90.59 kg CO2e, respectively. Water consumption was lowest for the EW-T-02 wooden wall (0.08 m3) and highest for the EW-M-02 masonry wall (0.19 m3). Conclusively, our analysis of passive house external walls demonstrates that wood-based systems offer superior performance in terms of materials, thermal efficiency, and LCA indicators, positioning them as the preferred option for sustainable passive construction.