The impacts of applying typical and aesthetically–thermally optimized TiO2 pigmented coatings on cooling and heating load demands of a typical residential building in various climates of Iran

• Typical and thermally–aesthetically optimized TiO2 pigmented coating were applied on conventional roofing material of a typical residential building in Iran.
• The impacts of applying typical and optimized coatings on peak and annual cooling and heating load demand were studied.
• The effectiveness of using these coating in various climates zones of Iran was discussed.

Cooling energy accounts for a significant portion of the total electricity consumption in residential sector during summer. While typical TiO2 pigmented coatings can be applied on roofs to reduce the heat gain to the buildings in summer but their high brightness makes them inappropriate for the roofs that are exposed to eye sight. The optimized TiO2 pigmented coating with low visible reflectivity to keep the darkness and high near infrared (NIR) refelectivity and infrared (IR) emissivity to reduce the thermal effects has been introduced by authors. On the other hand applying TiO2 pigmented coatings on roofs may increase the heating load demand in winter. In this article the effects of using the typical and optimized TiO2 pigmented coatings on both cooling and heating load demand of a single-family home in different climates are studied. The radiation analysis is conducted using radiation element method by ray emission model (REM2). The results show that the optimized coating besides keeping the dark appearance of the roof reduces the annual cooling load by 4–31% while increases the annual heating load demand by 1.7–10%. For a shiny typical TiO2 pigmented coating the reduction in annual cooling and increase in annual heating loads are 5–37% and 2–15%, respectively.