Evaluation of Energy-Efficient Building Envelopes with Thermal Insulation for Iraqi Climatology

The application of thermal insulation significantly reduces construction costs, enhances building performance, and improves occupant comfort. This study examines strategies for cooling buildings under Iraqi climatic conditions while minimizing electricity consumption. The thermal performance of building envelopes was assessed by analyzing insulation placement (external, internal, and central) and wall orientation. The findings indicate that polystyrene and mineral wool substantially reduce heat transfer and cooling loads, while wall orientation and moisture content critically influence efficiency. Multi-layer walls with insulation positioned at the core demonstrated superior thermal resistance, underscoring the importance of material selection and optimized wall configuration for hot climates. Energy measurements conducted in a dedicated test chamber, validated against theoretical calculations, showed that thermal insulation reduces total heat transfer by up to 50%, with actual-to-predicted energy consumption ratios ranging from 73% to 78%. Analysis of U-values for three-, four-, and five-layer walls revealed that a three-layer wall with central insulation offers the most efficient balance between energy performance and cost. The results provide practical design guidance for sustainable, climate-adapted building envelopes that optimize thermal performance, structural integrity, and economic feasibility.