C39 -- Assessment of the Environmental Impact of Hydronic System Choice in an Air Source Heat Pump

Air source heat pumps (ASHPs) have experienced widespread adoption across the globe. However, a comprehensive assessment of the environmental impact of ASHPs throughout their entire life cycle, including infrastructure choices and their impact on the built environment particularly in the residential sector, remains notably scarce in existing research. This study aims to analyze the environmental impact associated with the hydronic systems associated with the heating systems (ASHP or natural gas boiler). For the analysis, each hydronic system is designed based on the envelope requirements and heating system and further CIBSE methodology is adopted for the carbon quantification. Based on the analysis radiators paired with ASHP have an approximate embodied carbon value of 1676 kg CO₂e, compared to underfloor heating which has an approximate value of 1752 kg CO₂e. Comparing the findings, radiators associated with the natural gas boiler have 300% lower embodied carbon value. Additionally, this study suggests the need for a critical evaluation of radiator based heating solutions in the context of ASHPs. Furthermore, findings from this study can be further quantified for hydronic system selection based on different building typologies from new buildings to renovated buildings. Figure 1 shows the outline of the study undertaken.