Separate meter and electricity tariff for air-to-water heat pump sensible?

Worst/Easiest standard you can take. 15cm is already borderline.

This is a tight installation - 5cm! But then it is also the triple amount of pipes.

But it only works if each circuit is no longer than 100m. How many circuits are there? How long?

It is definitely future-oriented, consumption-optimized, and beneficial to the value of the house in the future. And if I am already going to spend half a million on a house, I want it done properly. And not just "it's good enough."

Material costs are almost negligible - 100m MSV pipe costs under €100. Stapling just takes longer.

But it only works if each loop is no longer than 100m. How many loops are there? How long?

There are three loops in just under 25 sqm. The pipe length is each just over 100m. Virtually a perfect landing.
It is not a self-created design, but calculated by the engineering office according to the room heating load.

There is just somewhere a sweet spot. (From the feeling, it should be around 8 cm. Although that also depends on the pipe thickness...). And of course, the leverage is smaller the better the house is insulated.

The pump does not necessarily have more work to do when the distances are smaller. Two circuits on the same area means less flow per minute again. More important for the pump are proper supply lines between the distribution boxes and the heat pump.

This shown "extreme" has a total heating circuit length of approximately 500 m at a real 5 cm!!! with 25 sqm. Far from 3 x 100 m.

This shown "extreme" has a total heating circuit length of about 500 m!!! with 25 sqm at a real 5 cm. Far from 3 x 100 m.

No, it does not - as said, each is a little over 100 m. And they are real 5 cm. I laid them myself ;) In the end, it’s not a problem if there are circuits over 100 m sometimes. It’s an interplay of various factors (pump, temperatures, pipe diameter, etc.)