Abstract
Achieving and maintaining indoor thermal comfort is a crucial factor for energy saving and human health, especially in heavily occupied public buildings, such as mosque buildings. The acceptable level of thermal comfort should not be achieved at the expense of damaging the environment by using preventable energy depletion. This study aims to investigate what level thermal comfort is achieved and related issues in mosque buildings in Abha city, which has a semi-arid moderate/cold mountainous climate. The research involved a computer modelling investigation by using Thermal Analysis Software (TAS). A number of comparisons of the simulation results with actual measurement data in mosque buildings, such as temperature, relative humidity, and energy demand were conducted. Main factors influencing thermal comfort and PMV were investigated for the selected mosques. In addition, thermal performance of mosques' fabrics and envelopes in terms of solar gain and heat loss/gain by conduction and its impacts on thermal comfort and energy demands were also discussed. The outcome showed some discomfort due to heat gain in summer and heat loss in winter. The results also revealed that the main factors behind heat gain or loss were the poor quality of the investigated mosque buildings' envelopes, including walls, roofs, floors, windows, and doors.