Abstract
The Ministry of electricity and water in the Kingdom of Saudi Arabia (KSA) reported (2013) that high temperature in summer months leads to an enormous increase demand in the air-conditioning electric load [1]. This work is aiming for investigating a possible mitigation to this critical problem. In this work, one of the Riyadh city (the capital of KSA) big mosques is identified as a model to explore the most appropriate ways to conserve energy since the mosques are established in dispersed locations of the KSA cities and operate simultaneously in prayers times. For the purpose of investigating several ways to reduce the energy consumption in these mosques, this study used the software named "eQUEST" (Quick Energy Simulation Tool) to investigate the effect of zoning areas, different types of roof construction, window glasses size and sunshield, heat transfer coefficient of the mosques' walls, roof and windows, impact of insulation material and thickness. All of these factors help in reducing energy consumption in mosques and hence contribute in energy conservation and saving in billing costs.