Radiators are often increased in size when replacing boilers with heat pumps, to deliver sufficient heat at lower heat pump flow temperatures. However, the existing survey methodology for assessing required radiator sizes carries significant uncertainty. A large empirical analysis of c.4600 boilers in the UK, produced in collaboration with the Department for Energy Security and Net Zero (DESNZ), suggests that these survey methods may overstate the necessity for radiator upgrades when retrofitting heat pumps (Childs et al. 2024). Hence, current practices may add unnecessary costs and disruption to heat pump installation. However, larger radiators will improve heating system efficiency, through lowering of flow temperatures. The resulting improvements in running costs, operational emissions, and peak electricity loads associated with larger radiators will therefore need to be weighed against the potential for faster and cheaper heat pump installation with less radiator upgrades. But, to optimise this trade off, understanding the uncertainty associated with existing heating system sizing methods is essential. This is why this PhD investigates the potential of a “radiator performance gap”, for the first time, comparing radiator performance analysis using survey methods to data driven methods, to add to the discourse of the most effective way to decarbonise heating in the UK.

Publications:
Predicting the heat pump readiness of existing heating systems in the UK using diagnostic boiler data