Abstract
Recent research indicates that heating, ventilation and air conditioning (HVAC) contribute up to 20% of new buildings' greenhouse gas (GHG) emissions. Additionally, such systems require several replacements throughout the building's lifespan to guarantee optimal operation and comfort. However, data on service life (SL) for technical installations remains insufficient or inconsistent across guidelines, leading to varying interpretations that affect emission calculations. This study evaluates how the service life of ventilation components influences the GHG emissions of an office building located in Bergen, Norway, as part of the work within the Research Centre for Zero Emission Neighbourhoods in Smart Cities (ZEN). Through life cycle assessment (LCA), GHG emissions from three replacement scenarios over 60 years were estimated and compared with the embodied emissions of the initial construction stage. Results indicate that replacement emissions range from 0.43 to 2.52 times the production stage emissions, depending on substitution intervals. The findings highlight the sensitivity of the service life parameter on GHG emissions and emphasise the need for reliable data on service lifetimes of ventilation components. A comprehensive database would improve calculation accuracy, and an increased industry focus on Environmental Product Declarations (EPDs) would enhance transparency and emission reduction efforts.