This paper presents actual performance of high-reflectivity paints by environmental exposure test. Test panels were coated with high-reflectivity or conventional paints on site or in-factory at the manufacturing stage by a newly developed heat curing paint method. Our results reveal that solar reflectivity of the panels were degraded by up to 20 percent from initial status during first year, and this degradation is chiefly due to airborne contamination. This study also demonstrates that panels coated with high-reflectivity heat curing paint with a photocatalyst finish can preserve high reflectivity and therefore thermal conditioning effects longer than the panels painted on site.
