Assessing the suitability of different roof types and coatings on roof-installed solar photovoltaic performance in sub-Saharan climates: a review

Abstract

Solar photovoltaic (PV) technology is widely adopted in sub-Saharan regions due to abundant solar irradiation and unreliable grid infrastructure. However, the performance of roof-mounted PV systems is significantly influenced by the type of roofing material and surface coatings used. This review evaluates the thermal and performance implications of installing PV systems on four common roof types—green, clay tile, metal, and plastic tile under sub-Saharan climatic conditions. Findings indicate that green roofs reduce PV module temperatures by 1.5–3 °C and improve power output efficiency by up to 6%, while clay tile roofs offer up to 2.6 °C cooling compared to metal roofs, resulting in a 0.378 V increase in output voltage per module. Coated metal roofs with reflective pigments such as TiO₂ and Fe₂O₃ were found to improve PV performance by up to 10.4%. This review concludes that roof material selection and coating application play crucial roles in PV efficiency and system longevity, with green roofs offering the highest performance gains but facing cost and maintenance barriers. This review also highlights research gaps in the comparative thermal performance of coated metal roofs, clay tiles, and plastic tile roofs, especially under varying sub-Saharan climatic conditions.