To get a more complete view of the energy usage & distribution in a household, it would be great to add the energy created/moved by a heat pump.
As you, for example, move 5 kWh into your house by spending 1kWh, I think that would ge a great insight in the actual energy used in a certain period.
This goes for heat used for heating your house and for heat used for heating your hot water, which usually are metered separately. So you would need to be able to add multiple ‘Energy created’ sources, just like “Solar panels”, for example.
I think this shoudl add another ‘bubble’ that adds energy to ‘Home’.
As for calculating the cost / savings: I’m not sure is that would be a necessary part of this feature, as the savings are only ‘virtual’ savings (you don’t actually get paid by moving this energy, you only use less energy to move the heat than by creating is).