Typical architecture designers convey through vague and qualified notions. With the increasing number of PV installations on buildings, architects are forced to corporate with technicians and engineers in the design processes. However, the communications between them are often hindered because unlike architects who communicate through semantic descriptors and visual images, engineers are used to interact with quantified terms. One way to solve this problem is adapting visual impact assessment for PV installed on façade so that one can foresee and evaluate its final overall effect in a way that is comprehensible for both sides. The visual impact assessment is a method mainly used in landscape design for evaluating the influence manmade changes caused on natural landscape. Now it is vastly used on aesthetic assessment for wind farms being built on open landscapes all over the world. Comparing with wind farms, the relevant researches for Photovoltaics are rather underdeveloped. The estimation of visual effect created by integrating solar energy components on open landscape is rarely investigated, let alone on architecture where it is more complicated because more aesthetic factors are involved. With the increasing number of Photovoltaics installed or to be installed on architecture facades, it is necessary to develop a rational visual assessment tool to better evaluate the appearance outcome of the final installation. Based on summarizing research experiences and literatures from former visual impact assessments, this paper tries summarize the possible factors that are relevant for AIPV installation, and changes and extensions on existing theories are being made when necessary. The final results will benefit architects, engineers during the planning process, and eventually for law regulator in laying down clear and reasonable urban planning regulations regarding installing PV in urban areas. In the end, the author will apply the visual impact theory on a retrofitting project where AIPVs are assigned to be installed on a church in Lucerne, Switzerland.