The Impact of the Composition and Location of Thermal Insulation in the Building Envelope on Energy Consumption in Low-Rise Residential Buildings in Hot Climate Regions

As global temperatures rise as a result of climate change, there is an urgent need to find ways to keep buildings cool without increasing energy demand, especially in the residential sector. This is especially true in hot climate regions, where demand for air-conditioning drives high household electricity consumption rates, and, in some cases, overburdens the energy supply. This study evaluates the impact of thermal insulation type, thickness, and location on reducing the annual energy consumption in a representative low-rise residential building in Riyadh, the capital of Saudi Arabia, using the DesignBuilder energy simulation tool. The most effective materials and locations are identified, and the life cycle cost model is used to establish the optimum thickness in each location. Reductions in energy demand, CO2 emissions, and cost savings are also calculated, and these are shown to exceed those made by applying current Saudi building standards. The findings reveal that applying the optimal thickness of thermal insulation to the walls and roof of a two-storey villa significantly enhances its thermal performance and reduces total costs, cutting overall energy consumption, and carbon emissions by up to 42.5% compared with the base case model, with a cost savings of 33% over 30 years, life cycle savings of 86.1 USD/m2, and a payback period of 7.98 years. This study demonstrates the positive impacts of thermal insulation from both an environmental and an economic perspective, with the aim of increasing its application. Its findings are immediately applicable in other hot-arid regions, notably other Gulf states, and its focus on the importance of ensuring that building regulations that mandate thermal insulation are properly enforced gives it wider relevance in other climate regions.