Energy-saving benefits of thermal insulation and glazing in code-compliant office building in cooling-dominated climates

Abstract

Thermal insulation of wall and roof and high-performance glazing have potential to save energy in cooling-dominated climates. However, lack of careful selection of these options based on the climatic location can adversely affect their energy performance. The local building codes need to be revisited to ensure that the thermal insulation and glazing options fulfil their intended purpose in a given climate. In this context, this study was aimed at assessing the energy performance of thermal insulation (polystyrene) and glazing for different climatic locations. A multistory office building was simulated by using Ecotect software for typical climatic locations of Saudi Arabia. Considering uninsulated wall and roof with single-glazed windows as the baseline, three different cases were studied: insulated wall and roof with single-glazed windows, uninsulated wall and roof with double-glazed windows, and insulated wall and roof with double-glazed windows. In general, the energy-saving benefit of glazing was significantly higher than that of thermal insulation. Also, the collective application of double-glazing and thermal insulation according to the local building code could significantly save the cooling energy demand (ranging from 18 % to 28 %). Conversely, this code-compliance caused an increase of cooling energy demand by 55 % in Abha and by 20 % in Khamis Mushait. However, a sensitivity analysis of these two regions showed that the energy-saving benefit could be positive by proper choice of the heating and cooling setpoints. Besides research interest, the findings of this study will guide for necessary amendments in the building code, eventually contributing to substantial savings in cost and energy and reduction in CO2 emission.