Investigation of the use of external insulation materials in domestic buildings in hot regions considering various window-to-wall ratios (WWR)

Thermal insulation is a key element in buildings for efficient thermal performance and comfort. This case study investigated the impact of using external thermal insulation in buildings within the context of the hot region of Saudi Arabia, showing the effectiveness of external insulation with respect to various elements, such as energy consumption, solar gain, and indoor air temperatures. The computer modelling tool (TAS EDSL) was used to predict the energy performance of the building. Moreover, on-site experimental work also used which focuses on increasing the glazing area from 12% to 40% of WWR. In addition, the study includes a real experimental investigation to evaluate the increase of WWR from 12% to 40% on the western side of the building. The analysis revealed that the use of external thermal insulation can save up to 60% of energy consumption compared to the absence of thermal insulation, reflecting the high performance of External Thermal Insulation ETI. Maximising WWR can contribute to a 1°C increase in the indoor air temperature for every 10% increase in WWR in the east orientation. The findings of the paper can feed the industry in various ways such as buildings regulations, sustainability and new launched national initiative Saudi Architecture. In conclusion, the WWR should not exceed 20% to ensure high thermal energy performance and to meet the required expected daylighting indoors.