Comparative analysis of heating and cooling solutions for residential use: Energy, environmental, and economic perspectives

This paper examines the techno-economic performance of domestic heating and cooling technologies across different climates. The novelty lies in the comprehensive assessment of a broad range of technological options using advanced thermodynamic and component-costing models. A holistic, like-for-like comparison is conducted for combinations of technologies that meet all residential energy needs – space heating, domestic hot water, space cooling, and electricity. Nine different system combinations are proposed, including natural gas boilers, photovoltaic systems, photovoltaic-thermal systems, solar thermal collectors, hydrogen boilers, air-to-water heat pumps, diffusion absorption refrigeration systems, and air-to-air air conditioners. These are analyzed for a typical single-family house under three distinct European climates: Athens (Greece), Strasbourg (France), and Helsinki (Finland), focusing on energy, economic, and environmental factors. From an economic perspective, the integrated photovoltaic - heat pump system configuration consistently has the lowest levelized cost of energy (LCOE) across all locations, ranging from 0.15 €/kWh in Athens to 0.20 €/kWh in Strasbourg. The photovoltaic-thermal – heat pump system configuration follows with a slightly higher LCOE than the photovoltaic – heat pump system (by 0.05–0.06 €/kWh) due to its higher initial costs. In general, solar integrated systems have an LCOE that is 0.10–0.20 €/kWh lower compared to the same systems that do not use solar energy. The payback time for the photovoltaic – heat pump system ranges from 4.65 years in Finland to 8.95 years in Greece. Standalone heat pump cost savings vary significantly and are lowest in Athens (403 €/year) and highest in Helsinki (2560 €/year) when compared to gas boilers, influenced by the regional electricity-gas price ratio, which is higher in Greece. However, photovoltaic and photovoltaic-thermal systems achieve a higher emission reduction in Athens (e.g., 4.70 tons of CO2,eq/year for the photovoltaic – heat pump system), due to the carbon-intensive grid of Greece. Although hydrogen boilers show a high emission reduction in Strasbourg and Helsinki (4.27 tons of CO2,eq/year), they exhibit higher LCOE than other systems (> 0.60 €/kWh), with their future viability depending on green hydrogen production costs. Overall, this study provides insights into residential energy systems across diverse climates, highlighting the importance of context-specific technology choices.