Costs for plumbing & heat pump

I see it differently. If the floor plan is sensibly designed, the routes for the pipes are short. Then hot water arrives quickly. The circulation is therefore often used as a fix for bad planning. The ERR is usually no longer needed. But only with proper planning and installation. Even with my radiator system, I set the central heating once and we always have our comfortable temperature in the house. No one has to adjust anything anymore.

I do not plan the floor plan according to WW routes, but so that I feel comfortable and have my rooms the way I want them. I am not interested in energy loss, just as I am not interested that my car needs 15 liters of SuperPlus as long as it gives me pleasure. Only senseless waste, that is poor planning.

In the same way, an ER control system makes sense to me, as on certain days I want more heat in different rooms.

I see it differently. If the floor plan is planned sensibly, the routes for the pipes are short. Then hot water arrives quickly. The circulation is often used as a correction for poor planning. The ERR is usually no longer needed. But only with proper planning and installation. Even with my radiator system, I set the central heating once and we always have our cozy temperature in the house. No one has to touch anything anymore.

I cannot confirm that. Our technical room in the basement is optimally positioned so that the bathrooms on the ground floor and the floor above are directly above it. Without circulation, at least 2-3 liters run through the tap before it gets warm/hot.

Circulation definitely passes 2-3 liters through the tap until it becomes warm/hot.

Correct: Water volume in the pipe = length*Pi*R² (the result is then in m³, so multiply by 1000 for a value in liters). For 10m from the utility room to the bathroom upstairs, it would be 3.141 liters with d=0.02m. The thread starter has pipe lengths over 10m here.

I don't plan the floor plan according to hot water routes, but so that I feel comfortable and have my rooms the way I want them. I am not interested in the energy loss, just as I am not interested that my car consumes 15 liters of SuperPlus as long as it gives me pleasure. Only senseless waste is poor planning..

In the same way, control of the ER makes sense to me, since I want more heat in different rooms on certain days.

We have different views on waste. That's not a problem, because it just is. If you have a reasonable planner or architect, you can combine both the comfort factor and the energy aspect.

I find running 2-3 liters of water through before hot water arrives annoying. In contrast, a circulation system burns a lot of energy (and money). I prefer to accept a little water waste rather than senselessly running hot water with corresponding losses through the house.

But that is also my personal opinion. For long pipe runs, I might consider alternatives. There is always a solution.

Flushing 2-3 liters of water before hot water arrives, I find annoying. In contrast, a circulation system consumes a lot of energy (and money).

Well, there are very energy-efficient pumps. They don't run all day, but according to demand and time. Even with circulation, the pipes are insulated.

Isn't the electricity cost for circulation estimated at around €30 per year?