Building renovation plan - introducing energy and cost into the managerial perspectives: A case study

Implementing more stringent energy requirements for public buildings has the potential to expedite the renovation rate of building stocks. While many studies have explored optimal renovation solutions to reduce energy consumption and cost, few have established a comprehensive building portfolio strategy from the perspective of portfolio managers. This study addresses this gap by developing a framework that empowers building portfolio managers to make informed decisions regarding building renovations. Through an in-depth case study, the current workflow for determining renovation needs, which involves analyzing maintenance requirements, building usability, and adaptability, is enhanced by incorporating a cost-optimal renovation framework. The study utilizes building simulations and life cycle cost analysis to assess the energy reduction potential of six school buildings requiring renovation. The results demonstrate a potential for energy use reduction, ranging from 11% to 44% when incorporating energy-saving measures into the renovations. Cost-optimal solutions are achieved for two buildings, resulting in energy reduction ranging from 31% to 36% and cost reduction ranging from 7% to 8%. The primary contribution of this research is developing a framework that reduces ambiguities of which buildings a portfolio manager should prioritize for renovation. By identifying current performance and improvement potential, the framework enables benchmarking against energy performance classes, aiding in strategic decision-making. However, the study also underscores the complexities of assessing a diverse building stock from a bottom-up perspective. Barriers such as obtaining high-quality data, scaling assessments, time constraints, and knowledge transfer are problems to overcome. Additionally, evaluating various building typologies with diverse characteristics, including those with legal restrictions due to heritage status, presents unique challenges. Future research directions should focus on expanding the framework to incorporate a life cycle assessment perspective. This approach will ensure a comprehensive building portfolio strategy that mitigates the risk of sub-optimal solutions.