Construction costs are currently skyrocketing

The crazy thing is, I’m even getting a modulating heat pump, but it supposedly can’t modulate low enough. My suspicion: they are calculating with 35-38°C flow temperature, correspondingly wide installation distances for the underfloor heating, and for these temperatures, the heat pump can’t utilize its modulation range at all.

Unfortunately, the heating technicians are doing too well, so 95% of them don’t even engage in this discussion.
What a shame!

The heating technicians simply don’t have time for discussions. Probably not even a handful of homeowners are interested in their heating system and how it works...
Besides, manufacturers offer packages and package prices that are better discounted. It is therefore understandable why the heating technician wants to install the whole shebang.

The crazy thing is, I am even getting a modulating heat pump, but it allegedly cannot modulate low enough. My suspicion: They are calculating with 35-38°C supply temperature, correspondingly wide installation distances for the underfloor heating, and for these temperatures, the heat pump cannot utilize its modulation range at all.

Would you like to mention the model designation of the heat pump and some key data? (KfW standard, m2 exterior surface, type of heat pump?)

The crazy thing is, I’m even getting a modulating heat pump, but apparently it cannot modulate deeply enough. My suspicion: They are calculating with 35-38°C flow temperature, corresponding to wide installation distances for the underfloor heating, and for these temperatures the heat pump cannot exploit its modulation range at all.

And that is the problem. The calculation and the corresponding installation are crucial. If these are done incorrectly, even the best heat pump won’t help you anymore.

The heating guys simply don’t have time for discussions. Probably not even a handful of the homeowners care about their heating system and how it works...
Besides, manufacturers offer packages and package prices that are better discounted. So it is understandable why the heating guy wants to install the whole bundle.

And then they wonder about the high electricity costs...

The heating technicians simply have no time for discussions. Probably not even a handful of homeowners are interested in their heating system and its functionality... Besides, the manufacturer offers packages and package prices that are better discounted. So it is understandable why the heating technician wants to install the whole kit.

yep, that’s called profit maximization, and it’s not only the heating technician who profits from installing it, but also the manufacturer. Heating systems used to be overdimensioned by 30-50%. Only no one cared about that with gas.

To take a bit of the hysteresis (haha) out of the heat pump topic:

I once started a thread here with plans for my design. The reactions were worrying.
Completely standard 0815 design.

After the first heating season, the conclusion: Not so bad.
Heating and domestic hot water consumption from summer '21 to summer '22: approx. 2000 kWh for 150 m² Kfw55 timber frame house after the first "blind" optimization.

Qualifications:
- In the bathroom, the electric fan heater ran when the kids were bathed. Should have been max. 100 kWh.
- Wood stove. No idea how much was burned, mostly leftover wood from construction.
I estimate the stove ran on 2/3 of the days at temperatures around or below 0 degrees.
- Night setback because of photovoltaic
- Open staircase to the unheated basement.
- No buffer tank

Just to show that a poor design doesn’t necessarily mean the death of energy costs.
But sure, better is always good! ;)