New heating system with hot water preparation?!

So,

the house is from 1937 and was renovated inside in 2013. The roof and ceiling were insulated. According to the current owner, only the basic walls remained. These are 40 or 45 centimeters thick.

The heating works without problems, was serviced every year, and also got a new burner last year. What worries me a bit is the instantaneous water heater in the basement. It is a 24kW instantaneous water heater.

The gas heating is only for heating!

I have already considered the domestic water pump and it would be cheaper in terms of electricity than the heater! Or am I seeing it wrong?

Where can I find a professional who calculates this?!

Thanks in advance for your answers!

What worries me a bit is the instantaneous water heater in the basement. It is a 24kW instantaneous water heater.

Why? Because of the relatively long line to the consumer?

Why? Because of the rather long line to the consumer?

For example. And that the electricity costs become high. Or am I mistaken?!?

For example. And that the electricity costs will rise. Or am I mistaken?!?

So in our last rental apartment, we had a new tankless water heater. The electricity costs were very reasonable. However, it was installed directly in the bathroom, which bordered the kitchen, so the wiring was very short.

Don't know how old he is. But at least [Bj.2013]. So from the basement to the bathroom or kitchen it is at least 15m‍♂️

I have already considered the domestic water pump and it would run more economically in terms of electricity than the heater! Or am I wrong?

Yes, that's correct. About 3 times less. And unlike instantaneous water heaters, it is suitable for photovoltaic power due to the low power consumption. On the other hand, there are installation and purchase costs.