The paper proposes a complete experimental characterization of an acrylic white paint, widespread in the field of household appliances or automotive sector. This paints has been already studied by means of in-lab tests; results have suggested that it is suitable for cool roof application. In this study, the results of a measurement campaign are discussed; it has been carried out by means of test room of the University of Sannio, in Benevento city, under Mediterranean climatic conditions starting from the summer 2016 until the summer 2017. In detail, the in-field monitoring concerns: all data for describing indoor and outdoor climatic conditions; the measure of solar reflectance at start and after one year from paint's application; the indoor and outdoor surface temperatures, the heat flux; optical investigations in visual and infrared field. The proposed paint has been compared with a commercial cool roof product and with a polished aluminum varnish in term of improvement respect to traditional dark bituminous membrane. Also the in-field aging effect is studied to compare degradation of proposed paint and commercial cool paint. Data elaborations bring to interesting conclusions; first of all, the in-field performance of acrylic paint is comparable to cool product and it is better than aluminum paint. Proposed product shows very fast drying, good gloss and appearance, lower application time and positive economic analysis. However, the aging is faster with in-field reduction of solar reflectance of around 20-25%. It could be due to application technique and to adopted product to favor the adhesion. This makes suitable other researches also for evaluate the application of a protective gloss that could assure greater durability than traditional product.