Effects of building façade architectural design elements on thermal comfort and energy efficiency

Abstract

Thermal performance, energy demand, and environmental sustainability in hot-arid climates—where cooling loads dominate—are strongly influenced by façade design. This study assesses the effectiveness of a passive curtain wall strategy through an experimental comparison of two structurally similar educational buildings in Iraq. Building A features a detached curtain wall positioned 1.40 m from the main envelope, while Building B employs a conventional single-skin façade. Field measurements were conducted in August 2025, during the hottest period of the year, under identical climatic conditions. Air temperature, relative humidity, heat flux, and indoor and outdoor surface temperatures were recorded at 30-minute intervals over five hours. Unsteady heat transfer through the envelope was analyzed using a one-dimensional steady-state heat conduction model. Results show that Building A achieved an average heat flux reduction of 11.35% compared to the reference building. This reduction led to lower surface temperatures, decreased heat transfer, and improved thermal comfort. The decline in heat gain implies reduced cooling energy demand and operational carbon emissions—an important consideration in regions with limited energy resources. The findings provide empirical evidence supporting climate-responsive passive façade strategies as an effective approach to enhancing energy efficiency and sustainability in hot-arid environments.