Assessment of energy poverty in Estonia: a spatial analysis of heating affordability and solar heating solutions

• Heating affordability varies strongly across Estonia due to income, building efficiency, and DH tariffs. • Pensioner households face the highest heating cost burdens in many DH-connected municipalities. • PV-powered heat pumps reduce DH consumption substantially and deliver the most consistent affordability gains. • Solar thermal collectors reduce DH consumption more modestly because much of annual output cannot used. • The effectiveness of decentralised solar integration depends on local building density and demand matching in DH systems. District Heating (DH) systems supply a large share of space heating in Europe and are increasingly adopted as low-carbon solutions. However, their implications on heating affordability and energy comfort depend strongly on energy prices, building efficiency, and household income, which have yet to be explored in detail. Also, there is a lack of understanding of the role of individual heating solutions in tackling energy poverty. This study aims to analyse the impact of coupling DH and rooftop solar heating solutions on energy affordability in Estonia using municipal-level georeferenced data. A two-stage analytical approach is applied to multi-family residential buildings, combining spatial mapping with scenario-based modelling of solar energy potential. In the first stage, heating affordability is assessed using the heating cost-to-income ratio, derived from household income and building energy performance indicators. In the second stage, household-level scenarios are modelled in which a part of space heating demand is covered by solar-powered heat pumps or solar thermal collectors, accounting for regional variations in solar irradiance and ambient temperature. The results indicate that PV-powered heat pumps can reduce DH consumption substantially, lowering average specific heat consumption from around 147 kWh/m 2 y to 75 kWh/m 2 y. On the other hand, the energy fraction from solar thermal collectors is limited to 130 kWh/m 2 y, because only 27% of annual energy output can be used to reduce heating cost under the assumed operating conditions. These findings illustrate the benefit of supplementary solar heating on heating demand and heating cost burdens in district-heated residential buildings, thereby offering relevant insights for policymakers and urban planners in regions with high DH penetration.