The energy performance of buildings and the high consumption of traditional building materials are considered to be the most important aspects that are related to the implementation of the sustainability concept in the construction industry with respect to the natural environment. At the same time, another important global ecological problem is represented by different types of waste resulting from existing industries. Therefore, it is necessary that civil engineering specialists find new solutions and materials that can improve the thermal and environmental performances of buildings by taking into consideration the large amounts of existing waste. Taking into account the fact that concrete is the most used material in the construction sector and that concrete elements have a significant influence over the overall energy performance of a building, the present paper takes under observation the use of tire rubber waste as a replacement for concrete aggregates. This study considers a replacement of 10%, 20%, and 30% of the 4–8 mm aggregates with crumb rubber cylindrical granules. The resulting values show an improvement in the thermal performance, but at the same time, the mechanical properties are reduced.

Due to the need of sustainable development of the building sector, it is important to increase the energy efficiency in buildings and reduce the energy consumption for heating and cooling. In a changing world, full of innovative solutions and technologies, passive strategies of vernacular architecture are more used to achieve life quality and eliminate the negative impact on the environment and human health. The vernacular architecture is based on the local construction materials and influenced by the traditions, culture and climate of the place. The “architecture without architect”, used mainly in housing, evolves over time and reflects the level of technology and historical context of the building. The core of this type of buildings was to use architecture to collect free energy from natural environment. Demonstrated over time, the inherent and timeless knowledge of vernacular architecture offers the basic level of comfortable living without the active strategies that include technologies. Passive architecture strategies are defined by minimizing or avoiding the energy consumption, using architecture and the natural environment to produce heating, cooling, ventilation and light. The elements of the natural environment are the sources of the energy: the sun, the earth, the air – the wind, the water. By adding active technologies, the quality of living must increase, but without influencing the main resources gained through passive strategies. The present paper will provide the information needed to understand the importance of the vernacular architecture’s passive strategies, as well as describe a few examples of those strategies in different parts of the world, examples that demonstrate the efficiency and the impact of these systems. The authors state that the use of those strategies in the first stage of architecture design helps to achieve easier the energy efficiency required nowadays and represents the fundamental base for passive houses and nearly zero energy buildings.

The global effort to reduce energy consumption generated by buildings involves the increasing use of thermal insulation materials, with expanded polystyrene representing one of the most used materials to this end. The thermal performance of expanded polystyrene has been extensively studied; however, information on the effect of exposure to cyclic environmental conditions on its thermal performance is limited. Therefore, we conducted such a study, which is presented in this article. In the first stage, samples were subjected to 28 days of preconditioning to accelerate the increase in moisture in the material. The second stage involved exposure to 40 freeze–thaw cycles of 12 h each. The weight and thermal conductivity of the samples were measured before and after exposure, and the compression behavior was also analyzed. The results show a decrease in the thermal performance of expanded polystyrene exposed to cyclic environmental conditions, as demonstrated by an increase in the water content of the material under the same measurement conditions and an increase of 5.06% in the average thermal conductivity. The influence of this increase on the thermal performance of commonly used wall construction elements was also been studied and presented in this article. A decrease of 7.59% in the compressive stress of the material at 10% strain was also demonstrated.

Daylighting design is not only dimensioning glazed surfaces to provide sufficient natural light to an occupied space but also a method of analyzing how this can be achieved without unwanted effects, such as gains and losses of heat, glare, and variations in daylighting intensity at various indoor distances and levels. The case study presented in this paper highlights the energy consumed due to a group of windows with a large glazed area in an existing building located in a temperate continental climate area. The energy consumption results from supplementary artificial lighting required to maintain adequate illumination for indoor activities and to counterbalance heat loss during colder periods are evaluated. The analysis performed by modifying the glazed surface led to the identification of an optimum value of window dimensions for minimum energy consumption. The results of the case study highlight the fact that the evolution of the total energy consumption, evaluated as the sum of the energy consumption due to additional heating/cooling and the artificial lighting required to compensate for the reduction in natural light, is strongly influenced by the dimensions of the glazed surfaces, as well as the minimum level of lighting imposed by the regime of activities carried out in the building. Thus, the outcomes obtained in the research show that at lighting values below 500 lx, the total energy consumption is directly proportional to the glazed surface. From values of 500 lx for the illuminance level, the total energy consumption drops from 2730 kWh/year for a window height of 230 cm to 2399 kWh/year for a height of 110 cm, after which it starts to rise again, reaching a value of 2786 kWh/year for a height of 30 cm. This phenomenon is also found at values higher than 500 lx; accordingly, for an imposed lighting of 1000 lx, the minimum total consumption is identified at a window height of 150 cm. The case study presented in this paper clearly highlights a complex relationship between the height of the glazed surface and the energy consumption required to compensate for heating or cooling and the reduction in natural lighting. Lower window heights reduce heat loss or gain but also correspondingly increase the energy consumption of artificial lighting.

There is an international concern for reducing energy consumption and protecting the environment in the construction industry. The energy efficiency of a building depends on the thermal resistance of concrete, and utilizing concrete products with elevated thermal resistance can enhance this aspect. This study analyzes the impact of perlite, as an addition, on the physico-mechanical properties of concrete, with the aim of identifying perlite concrete products that will respond to the improvement of the heat transfer resistance of the building envelope. The study examines the effect of replacing different amounts of concrete aggregates with perlite in percentages of 10%, 20%, 30%, and 100%. The results show that substituting sand with perlite improves the thermal performance of concrete, but its mechanical properties are negatively affected. The research carried out highlighted that perlite can be successfully introduced in the production of concrete blocks used for external non-bearing wall panels, the outstanding feature being the reduction of energy consumption in buildings. Overall, the paper identifies an efficient and environmentally friendly way of using perlite in the construction industry, enhancing the energy efficiency of buildings while minimizing the environmental footprint caused by the construction industry.

The construction industry is a key driver of environmental change due to its extensive ‎use of resources and high levels of emissions, thus placing a significant burden on global ‎efforts towards sustainable development targets. A large portion of the environmental ‎footprint of buildings results from the energy required to sustain indoor comfort levels. ‎Therefore, enhancing the energy efficiency of existing buildings becomes critical in ‎reducing their environmental impact. This study examines the influence of increasing ‎thermal performance with the aim of reducing heating ‎demand. Thus, numerical modelling tools and different energy performance assessment meth-odologies have been used. ‎Specifically, it evaluates two existing residential buildings in Romania and compares ‎heating demand predictions using PHPP and Mc001-2022 methodologies across various ‎climatic data sets and case studies. The results reveal significant variability in heating ‎demand predictions, emphasizing the importance of methodological choice and climatic ‎data. The ‎study highlights that both PHPP and Mc001-2022 methodologies yield varying results ‎depending on the specific conditions and characteristics of each building. This variation in results underscores ‎the necessity for a nuanced and context-specific approach to energy performance ‎assessment, in-corporating multiple energy efficiency measures tailored to the unique ‎features of each building.