Quantitative Evaluation of BIPV Visual Impact in Building Retrofits Using Saliency Models

BIPV (Building Integrated Photovoltaics) integration in urban spaces requires, not only careful technical, but also aesthetic considerations as its visual impact is seen as a kind of environmental effect. To manage this effect, different methods were developed to measure it; however, most existing evaluation methods are either based on subjective speculations and have no continuous criteria standards, or they do not show much relevance to neuropsychological findings. This paper presents an alternative and complementary method for evaluating the BIPV visual impact using the saliency method with an objective, quantitative and neuropsychological-based approach. The application of the method was tested and is discussed in the context of an example case study in Switzerland. Several different BIPV designs were developed for the case study, purposely in ways that made it difficult to rank their visual impacts with one’s subjective instinct. Using the proposed saliency method; however, the differences in BIPV visual impact across all designs could be identified, demonstrated and calculated sensitively. Potential applications of this proposed method include being a helping tool in deciding which BIPV design causes the least or most visual impact among others. Additionally, when combined with solar cadaster, the method enables a comprehensive estimation of BIPV potential in urban areas from both technical and societal aspects.