Sizing, safety, lifetime performance, environmental impact and costs of residential A-to-A heat pumps: Current and future scenarios according to new F-GAS regulation and EPBD

• Optimal design of residential heat pump for heating and cooling. • Compliance with the 2024 Fgas regulation and EPBD. • Highest performance solutions for propane limited by maximum refrigerant charge. • New 2024 buildings will consume up to 70 % less energy compared to the 1976 levels. • Propane has the lowest environmental impact, and performance comparable to R32. The 2024 F-GAS Regulation mandates the phase-out of fluorinated gases across multiple sectors, promoting the adoption of natural refrigerants like propane, which pose flammability risks. Simultaneously, the 2024 Energy Performance of Buildings Directive (EPBD) introduces stricter requirements for building thermophysical parameters, potentially reducing heating and cooling peak loads. Together, these changes will significantly influence the design and optimization of residential heat pump systems. This study aims to identify optimal heat pump design solutions for various building types—both existing and new EPBD-compliant structures—focusing on performance, environmental impact, and costs under the new F-GAS regulation. A numerical approach was used to simulate the performance of different air-to-air heat pump configurations, with cooling capacities ranging from 1.5 to 5 kW. Lifetime performance, total costs, and equivalent warming impact were evaluated across diverse climate conditions and room sizes, taking into account safety constraints from the EN378 standard on refrigerant charge limits. Preliminary comparisons of refrigerants show that R32 offers the best performance and cost-efficiency, while propane performs similarly but with the lowest environmental impact. R454C, however, performed the worst. In terms of lifetime performance, heat pumps in EPBD 2024-compliant buildings are projected to consume 30–40 % less energy compared to 2021 standards, and up to 70 % less than buildings from 1976. Furthermore, the reduced operational costs, especially in warmer climates, decrease the necessity for high-performance systems. Finally, we provide a methodology to extend these results to other European climates, in order to provide indications for both heat pump manufacturers, to face with correlation between required heating and cooling buildings loads, heat pumps energy classes and employed refrigerants, and policy makers, to remark the consequences on the heat pump market and to show various possible future scenarios