Abstract

The electrification of heat is central to achieving net zero targets in the UK, yet concerns remain regarding its impact on household energy afforda-bility and fuel poverty. While previous research has extensively assessed the technical and environmental performance of retrofit strategies, limited attention has been given to the interaction between building performance, heating sys-tems, and household income at the dwelling scale. This paper presents a bot-tom-up approach to assess fuel poverty risk by integrating Building Perfor-mance Simulation with an income-based affordability evaluation. A representa-tive UK semi-detached dwelling is analysed under multiple retrofit scenarios and heating technologies, including gas boilers, Air Source Heat Pumps, and di-rect electric systems. Simulated energy demand and consumption are translated into annual energy costs, which are then evaluated against household income across different income deciles. The results show that reductions in energy de-mand do not necessarily lead to improved affordability. Under current UK en-ergy prices, electrified heating systems can increase energy costs and exacer-bate fuel poverty risk. Minimum retrofit measures are found to provide the most consistent improvement in affordability, while the viability of electrification is highly sensitive to electricity price levels and tariff structures. The integration of on-site renewable generation further improves outcomes when self-consumption is considered. The study demonstrates the importance of incorpo-rating affordability into decarbonisation strategies and highlights the value of bottom-up approaches in supporting equitable transitions to low-carbon heating.