In the pursuit of sustainable and healthy learning environments, it is crucial to integrate indoor air quality (IAQ) and life cycle assessment (LCA) methodologies. This study presents the results of the integration of IAQ and LCA for enhanced sustainability in educational buildings. Two identical schools, one renovated and the other non-renovated, were selected for the study. Temperature, relative humidity, and CO₂ sensors were placed in different classrooms for two months. Collected data were then analyzed to compare the IAQ of the two schools. Additionally, a 3D model of the schools was created, followed by a One-click LCA analysis to assess the environmental impact of the buildings throughout their lifecycle. Non-renovated classrooms showed higher CO₂ levels, with maximum values reaching 4969 ppm compared to renovated classrooms’ maximum of 2247 ppm. Renovated classrooms had higher temperatures: 20.8–21.2 °C (heating season) and 23.3–24.0 °C (cooling season) versus 18.2–18.6 °C and 21.6–23.2 °C in non-renovated ones, while relative humidity was lower (mean of 39.3% vs. 45.2%). Renovated classrooms demonstrate better indoor air quality, but higher temperatures may require monitoring or mechanical ventilation to ensure optimal comfort. The combined IAQ and LCA analysis offers a more holistic understanding of the sustainability performance of educational buildings. This integrated approach underscores the importance of using both IAQ and LCA assessments to inform renovation strategies and policy decisions aimed at enhancing the sustainability and health of school environments. Notably, the Global Warming Potential (GWP) increased by 5.89% in renovated schools compared to non-renovated ones.