This study explores what drives the adoption of rooftop solar panels in Metro Manila’s urban buildings – a context where both technical and behavioral factors often make the decision complex. While renewable energy has been widely discussed, little research has examined how these two perspectives interact in dense city environments. To address this gap, the study draws mainly on the Extended Theory of Planned Behavior, supported by ideas from Diffusion of Innovations and UTAUT2, to understand how people’s perceptions and attitudes shape adoption. Design thinking framework was used for the qualitative study. The work connects directly to SDG 7 (Affordable and Clean Energy), SDG 11 (Sustainable Cities and Communities), and SDG 13 (Climate Action), highlighting its relevance to sustainable development. The research followed an embedded mixed-methods approach. Surveys with facilities managers provided broad insights into adoption patterns, while interviews added richer detail on personal and organizational experiences. Results show that perceived benefits strongly influence adoption decisions, while attitudes toward renewable energy, though positive, do not significantly mediate this effect. Technical feasibility was not a moderator but emerged as an important predictor. The interviews revealed practical challenges such as high upfront costs, regulatory barriers, and structural concerns alongside opportunities from new technologies and supportive policies. Overall, the study underscores the value of combining behavioral, technical, and design perspectives. It suggests that tailored solutions, stronger policies, and strategic partnerships can help accelerate the spread of rooftop solar in urban areas.

Keywords: rooftop solar panel adoption, Extended Theory of Planned Behavior (ETPB), Design Thinking Framework, renewable energy integration, technical feasibility, urban sustainability