Whom to entrust with the room-wise heating load calculation?

Oh dear, I see the next topic I need to read up on... Thanks ! I will consult the energy advisor. Of course, we could also go bigger than 10cm (15cm), but I thought that would be too big anyway. Intermediate steps are unfortunately not possible. That is probably the compromise one has to make with a low installation height.

As I said, the efficiency loss is significantly greater. If you downplay the pump costs that much, then according to your argument it makes even less sense to do without modulation.

Besides, cycling reduces the lifespan of the heat pump.

Why shouldn’t you be able to achieve a low build-up with a cycling solution as well?

I belittle them because 16 hours a day is nonsense, even with modulating, rather longer-running heat pumps.

Yes, cycling reduces the lifespan. But when does a heat pump cycle in a harmful way? 3, 5, 50, 200 cycles a day?
You read that the compressor is designed for 100,000 starts. With 25 years of use, that corresponds to 11 cycles per day.
The people who show up in forums with _really_ cycling heat pumps sometimes have over 100 cycles a day. That is bad.
But heating 3-4 times and adding hot water twice a day is far from a problematic situation in terms of durability.

So please keep things in perspective.
What you say is certainly all correct in theory, but the impact is not significant.

Anyone following threads on the topic of heat pumps here and reading my posts knows that I really am not a fan of this "as long as it’s warm" industry, and yes, there are a few rules to observe.

But this optimization mania down to the last little percent is no longer reasonable. The economic viability is hard to prove, and it also puts the executing craftsman in the impossible position of having to guarantee this excellence. Because all the great calculations are based on a lot of parameters and assumptions that don’t always have much to do with reality. And then the well-read building owner stands there wanting a warranty because the Tacco shows 0.1 l/min too little flow.

Everyone has their hobby, but a little less drama would really do some good. That only causes insecurity.

Do you remember the report about the craftsman in Bavaria who no longer wants to serve Audi engineers?
The discussions on the topic of heat pumps here and especially in the well-known specialist forum strongly tend in this direction.

The retrofit solution is about 1cm high (plus a thin layer of leveling compound). So far I haven’t seen a stapling system that can achieve that.

In this case, I would even be grateful to know which company I should avoid if I were a customer.