This study explores sustainable energy renovation strategies for a congregation building in southern Sweden using a parametric optimization approach to balance passive and active measures. Passive measures include envelope and window improvements and leakage control, while active measures involve photovoltaic integration and ventilation enhancements. The renovation aims to optimize energy use, thermal comfort, indoor air quality (IAQ), life cycle cost (LCC), and life cycle assessment (LCA). However, individual measures often conflict with other objectives. By integrating the optimization tool Opossum with ClimateStudio, which simulates energy, thermal, and photovoltaic panels (PV) performance, along with programmed LCC and LCA calculations, the study identifies optimal solutions. Results indicate a 24% energy reduction, 23% lower LCC, and 47% less CO₂ emissions without changing the existing ventilation system, though IAQ and comfort remain inadequate. With new ventilation, energy use increases, LCC rises by 53%, but CO₂ emissions reduce by 11%, resolving IAQ issues and improving comfort by 74%. The study acknowledges limitations due to data assumptions and simulation constraints; future work could include full building LCA and moisture assessments to enhance the findings.