Mobility paradox in compact cities: Rethinking energy equity in tropical informal settlements

Informal settlements in tropical urban areas present a complex paradox in energy performance: although characterized by compact urban form, they often exhibit significant thermal inefficiencies, inadequate daylighting, unsustainable material choices, and constrained spatial walkability. This study examines the multidimensional energy and mobility performance of buildings within the dense kampung area of Notoprajan, Yogyakarta, using an integrated analytical framework encompassing operational energy consumption, embodied energy assessment, spatial daylight autonomy (sDA and cDA) evaluation, and walkability metrics. Drawing on empirical field data and advanced digital simulation methods, this research reveals that high urban density does not inherently guarantee energy efficiency, thereby challenging conventional assumptions about compact urban development. Operational energy consumption in small-scale hospitality establishments was found to be nearly three times higher than that of single-family residential units, while material composition demonstrated profound influence on embodied energy profiles across the settlement. Critically, only 6% of surveyed buildings achieved the minimum sDA₃₀₀,₅₀% standard, and 18% met the cDA₃₀₀,₅₀% threshold, underscoring severe daylighting deficiencies. These findings underscore the imperative for passive design strategies, material substitution approaches, integrated spatial planning interventions, and enhanced pedestrian infrastructure to achieve sustainable retrofitting and promote energy equity in informal tropical urban contexts.