This paper analyses, as a case study, various balcony glazing arrangements in a typical tourist apartment building on the Mediterranean coast of south-eastern Spain, and their effects on the energy performance. The glazing of terraces has been very common in this type of flat over the last 40 years. The objective is to determine qualitatively and quantitatively how the glazing of terraces in such buildings influences their energy efficiency and indoor thermal comfort, considering the specific characteristics of the dry Mediterranean climate (BShs) within a warm semi-arid climate (BSh). The scientific novelty of the work consists of demonstrating that the installation of glazed enclosures on terraces allows the houses to be heated for free in winter, taking advantage of the greenhouse effect, and allows excess heat to be dissipated in summer by using natural ventilation. The results of the work enable the determination of appropriate terrace glazing solutions to improve the energy efficiency and thermal comfort of the dwelling, obtaining a reduction of more than 58% in annual energy demand and annual energy consumption. The work demonstrates the advantages that glazing systems for terraces can have in improving the energy efficiency of houses by using systems like glass curtains.

The energy-supply crisis, aggravated by the war in Ukraine, has prompted EU governments to approve urgent energy-saving measures. The new Spanish energy-saving standard aims to reduce energy consumption by changing the regulatory limits for indoor hygrothermal conditions in buildings. This regulation has provoked a great social debate about its real effectiveness and its impact on user comfort. This work explores the hygrothermal performance of an office building in southeastern Spain. The objective of this research is to determine qualitatively and quantitatively how the new energy-saving standard in Spain influences energy efficiency and indoor thermal comfort, by considering the characteristics of the dry Mediterranean climate (BShs) within a warm semi-arid climate (BSh). The scientific novelty of the study is to demonstrate that the new Spanish standard not only reduces energy costs but also makes the indoor comfort of buildings much worse; for this reason, an improvement in the standard is also proposed. The study methodology consists of a comparative study between the thermal performance, thermal comfort, and energy demand of the building, considering both the new and previous standards’ requirements. It also includes the evaluation of a proposal to improve the current standard. The results showed that the new energy-saving standard reduced energy consumption by 21.78% in comparison to former standards, but the new comfort ranges were not acceptable for 60% of the users. The proposed improvement does achieve acceptable comfort for most users (75%) and an additional reduction in energy demand of 48.76% compared to current standard. We conclude that the thermal comfort requirements of the current energy standard should be modified to better adapt the design criteria to the dry Mediterranean climate.

The dry Mediterranean climate (BShs) within a warm semi-arid climate (BSh) is the zone in Europe with the most annual hours of sunlight, and it has a smaller annual temperature variation than most climates. This allows the greenhouse effect caused by windows to be used to heat dwellings in winter. Balcony frameless retractable glazing systems known as “glass curtain” systems offer the highest proportion of glass and maximum openness in the façade, allowing for maximum sunlight and ventilation. This work studies a glazed terrace with a “glass curtain” in a dwelling on the Spanish Mediterranean coastline. The objective is to quantitatively determine the enhancement of the thermal comfort and energy efficiency of a dwelling using “glass curtain” systems. The modification of several design parameters of the glazed terrace is also analysed. The novelty of this study lies in demonstrating that the use and optimised design of “glass curtain” systems allows us to obtain nearly zero-energy buildings (nZEBs) and thermally comfortable dwellings all year round. The research methods include a comparison of the current thermal performance of the dwelling with and without a “glass curtain” system via on-site measurements. The study also evaluates the influence of modifying design parameters using computer simulations. The results show that “glass curtain” systems increase the indoor temperatures inside the dwelling by about 4 °C in winter and reduce the annual indoor thermal oscillation from more than 16 °C to only 10 °C. Consequently, such systems reduce heating energy needs by almost 60%. Glazed terraces using the proposed design parameters show further improvement regarding thermal comfort and practically eliminate heating and cooling needs.