Changing your internet provider will only impact your heating for any duration you do not have internet access. For as long as the Passiv Hub is not connected to the internet, you will not be able to control your heating using the Passiv App, and ecoHeat will not be able to use remote data such as weather forecasts when optimising your heating. Your heat pump will still be optimised using locally stored data such as tariff information, but this data cannot be changed until the system reconnects to the internet.
If changing your internet provider results in a new wireless router, make sure to plug the new router back into the Passiv Hub using an ethernet cable.