• Energy Research
• 12. Responsible consumption close

The construction industry is one of the largest consumers of natural resources, and the building sector accounts for around 40% of energy consumption and CO2 emissions. To contribute to the need for more sustainable solutions, this research analyzed and highlighted the benefits of off-site construction, utilizing eleven zero-energy prefabricated houses from the Solar Decathlon Middle East competition as case studies. The study used construction data documented by the competition organizers, such as drawings, manuals, photos, and in-person observations during the assembly process. The comparative analysis focused on the construction categories, types of solutions, structural materials, façade types, and building materials. The case studies featured both heavy and lightweight construction and three types of off-site construction: panelized, volumetric, and hybrid. The hybrid construction was the most utilized since it combines the advantages of less intensive on-site work of the volumetric solutions with the transportation benefits of 2D elements. The designers justified their selection of timber as a structural material based on its low environmental impact. In addition, they enhanced the environmental benefits of off-site construction by selecting eco-friendly materials and solutions that increase the efficiency of the houses.

Given the global energy and environmental situation, the European Union has been issuing directives with increasingly demanding requirements in term of the energy efficiency in buildings. The international competition of sustainable houses, Solar Decathlon Europe (SDE), is aligned with these European objectives. SDE houses are low energy solar buildings that must reach the near to zero energy houses’ goal. In the 2012 edition, in order to emphasize its significance, the Energy Efficiency Contest was added. SDE houses’ interior comfort, functioning and energy performance is monitored. The monitoring data can give an idea about the efficiency of the houses. However, a jury comprised by international experts is responsible for carrying out the houses energy efficiency evaluation. Passive strategies and houses services are analyzed. Additionally, the jury's assessment has been compared with the behavior of the houses during the monitoring period. Comparative studies make emphasis on the energy aspects, houses functioning and their interior comfort. Conclusions include thoughts related with the evaluation process, the results of the comparative studies and suggestions for the next competitions.