BAFA / KfW funding and heat pump tariffs

If it is only for proving the annual performance factor, the meter can simply be connected "in series" in the supply line to the [WP]. This way, no separate tariff can be billed, but you save yourself the cascade and the (sometimes) associated discussions with the energy supplier during billing.

And probably – but I am not sure about that – a [Hutschienenzähler] is sufficient for this. And not one that necessarily has to be provided by the network operator and paid for monthly.