Renewal of heating system in old building, which system?

What do you say about the heating company's statement that with the Vaillant VWL 125/6 A heat pump and the COP calculation, no heating element will be needed.

That you are either building on the Côte d'Azur or the heating company has not thought about cold winters. Just ask how the system is supposed to work during a week of -10 degrees if you actually need 50-55 degrees flow temperature. I know some new houses that are energetically clearly superior to your place, which need the heating element at -10 degrees – and the heating systems are designed for around +/- 30 degrees flow temperature.

Either you are building on the Côte d’Azur or the heating company didn’t consider cold winters. Just ask how the system is supposed to run during a week of -10 degrees if you might actually need 50-55 degrees supply temperature.
I know several new houses that are energetically clearly superior to your place, which need the heating rod at -10 degrees—and the heating systems are designed for around ±30 degrees supply temperature.

Yes, okay, I will ask. Although one has to say that here in Munich in recent years we have actually had very mild winters.
The average temperature in winter, I believe, was between +1.4 and +3.6 degrees. Even if the heating rod would be needed for a week at -16 degrees, it wouldn’t exactly "kill us."

As I said, the heating company justified this by saying they therefore sized the heat pump larger to avoid using the heating rod.

Best regards