The Weighted Impact of Public Space Perception Within Old Communities on Residents’ Happiness: The Mediating Role of Intergenerational Interaction

(1) Background: Age-friendly emphasizes creating an appropriate living environment for people of all ages, which plays a crucial role in promoting intergenerational interaction in community public spaces and is conducive to achieving sustainable social development. This study explores how residents’ views on community public spaces affect their happiness, with intergenerational interaction acting as a mediating factor. (2) Methods: The data were sourced from 36 typical residential communities in 12 subdistricts of Yangpu District, Shanghai. Field investigations and questionnaire surveys were conducted on these communities, and a total of 1048 valid samples were collected. Descriptive statistics and structural equation models were employed to analyze the data. (3) Results: This research reveals that overall environmental perception significantly enhances happiness, and intergenerational support mediates this relationship. Factor loadings indicate that education & training and elderly & childcare spaces are the most salient dimensions of environmental perception, underscoring fundamental role in shaping how residents form their overall evaluation of community spaces. Through their strong association with intergenerational support, play a significant indirect role in enhancing residents’ happiness. Community belongingness plays a reinforcing role between intergenerational support interaction and happiness. The analysis of individual attributes further reveals that the length of residence and gender have moderating effects on the perception of public spaces. (4) Conclusions: This study examines the path of “Environmental perception → Intergenerational interaction → Happiness” and identifies the key mediating role of intergenerational support in this relationship. The conclusions indicate that optimizing community public spaces, particularly by improving “empowering” and “protective” spaces and fostering intergenerational integration through activities, can enhance residents’ belonging and happiness, offering a pathway to advance the SDGs.