the performance of two solar air heaters (SAHs) constructed from recycled aluminum cans. Two configurations were evaluated: SAH-1 (rectangular, aspect ratio 4:1) and SAH-2 (square, aspect ratio 1:1). Experiments were performed in Cairo, Egypt, during February (winter), at tilt angles of 0°, 15°, 30°, 45°, and 60°, utilizing a thorough 4E assessment (energy, exergy, economics, and environment). SAH-1 exhibited enhanced performance, attaining a peak absorber temperature of 88.3 °C, a heat gain of 412.7 W/m2, and an overall efficiency of 50.9 % at a 45° inclination. Exergy efficiency attained a maximum of 72.4 %, while the sustainability index achieved 3.62, surpassing SAH-2 in all criteria. Economically, SAH-1 attained a reduced energy cost ($0.0028–$0.0056 per kWh, 15 % lower than SAH-2) and conserved up to 158.4 kg of CO2 yearly, compared to 134 kg for SAH-2.