Influence of Balcony Thermal Bridges on Energy Efficiency of Dwellings in a Warm Semi-Arid Dry Mediterranean Climate

Abstract

Thermal bridges significantly influence the energy performance of buildings. However, their impact varies depending on the type of thermal bridge, climate conditions, construction methodologies, and geometric characteristics of the building. On the Spanish Mediterranean coast, buildings with large balconies are predominant. Nevertheless, the Spanish energy efficiency regulations do not adequately specify the thermal bridges at the junctions of balconies with facades, leading to a lack of consideration for their influence in the majority of architectural projects. The objective of this study is to qualitatively and quantitatively assess the impact of such thermal bridges on the energy efficiency of buildings in a dry Mediterranean climate (BShs) within a warm semi-arid climate (BSh). As a case study, the influence of this thermal bridge is analyzed in two residential buildings located on the Mediterranean coast of southeastern Spain. The study also examines the modification of various construction parameters of this thermal bridge and determines the optimal design parameters to reduce its thermal transmittance. The results demonstrate that the energy needs caused by thermal bridges account for approximately 40% of the total annual energy needs of the studied residential buildings. Balcony thermal bridges account for 25% to 40% of the energy needs caused by all thermal bridges. The lack of differentiation in Spanish standards between balcony–facade and facade–slab edge junctions causes an imprecision in calculations equivalent to 12% of the total annual energy needs of dwellings. The novelty of this research lies in highlighting that current regulations and calculation programs need improvement to better characterize balcony thermal bridges and enhance the accuracy of building energy efficiency calculations.