The electrification of heat using heat pumps with renewable power presents an attractive and technically feasible pathway for decarbonising heating. However, until now, the uptake of heat pumps has been much slower than fossil-fuel-based heating, particularly in the UK. To accelerate the use of heat pumps for national-scale heat decarbonisation, this study proposes new approaches to synthesise high-quality temporospatial energy datasets (e.g. hourly depth-dependent region-based ground source temperature), a new framework that facilitates national-scale cost analysis using synthesised datasets rather than individual location-based analysis, and forward-looking analysis and discussions on potential subsidy structures and R&D directions for facilitating the transition to low-carbon heat using heat pumps. The results suggest that currently Renewable Heat Incentive (RHI) subsidised ground source heat pumps have the lowest levelised cost of heat (10-40% lower than gas boilers), benefiting from the high heating efficiency and the 'feed-in-tariff' style RHI subsidy. However, considering the change of future subsidies, required advances are analysed to improve the cash flow of owning heat pumps, improve heating efficiency,improve integration with low-cost power sources, and reduce heat demand via domestic energy efficiency improvements. These insights will help engineers and policy-makers to decarbonise domestic heat using heat pumps. (c) 2021 Elsevier B.V. All rights reserved.