Multiobjective optimization of retrofit insulation for near-zero energy residential apartments

Purpose This study aims to explore the potential of retrofitting external walls with insulation materials to reduce annual energy consumption in residential apartments and achieve near-zero energy standards. Specifically, it focuses on a building lacking initial insulation and uses a multicriteria model to evaluate the effectiveness of various thermal insulation strategies. Design/methodology/approach A genetic algorithm optimizes insulation thickness to minimize environmental impact (measured by global warming potential) while achieving near-zero energy consumption. DesignBuilder software simulates the building’s energy performance for various insulation scenarios, considering factors like material type, thickness and architectural constraints. Life cycle assessment assesses the environmental impact of insulation materials. Findings The study finds that rockwool and mineral glass wool (7–15 cm) paired with plasterboards (7–15 cm) offer the best balance between minimizing environmental impact and achieving energy efficiency. The findings suggest that achieving near-zero energy consumption in a single apartment unit is feasible without modifying other units or the building’s exterior walls. It highlights the need for an initial design framework considering both environmental impact and performance, despite variations caused by factors like location and building layout. Rockwool and mineral glass wool are identified as the most promising materials, offering a good balance between energy savings and environmental impact. Originality/value The research also emphasizes the ongoing efforts of manufacturers to develop thinner, more environmentally friendly insulation systems.