Is It Possible To Install A CO2 Heat Pump in My Old House with Old Radiators?

The typical temperature of the inlet and return for these radiators is 70°C and 50°C respectively, which is not ideal for the CO2 heat pump. However, if we don't want to spend a lot of money replacing all the radiators, we can simply replace the gas boiler with a CO2 heat pump and reduce the circulation flow. By doing so, we can lower the return temperature to below 40°C. Although this may not achieve the maximum COP (Coefficient of Performance) for the CO2 heat pump, it can still operate at a reasonable COP of 2 to 3, resulting in energy savings.