Construction costs are currently skyrocketing

195sqm, KFW 55, Zehnder controlled residential ventilation, geothermal energy.
about 2300-2500 kWh electricity with not too great annual performance factor

At 6000 kWh I would crush everyone into the ground. Botched work on purpose or what?

That is probably a standard statement by a heating engineer just thrown out off the cuff.
I wouldn’t take that as gospel, that’s just how it goes ‘on construction sites’ or did he really read through the detailed planning of the energy consultant (which are usually 15-30 pages)?
- probably not, why would he. The house is standard size, so it needs standard energy, meaning 1500m3 gas or 5 MWh electricity – a bit of buffer, done.

Of course, that suits a bigger, unnecessary heat pump again.

195sqm, KFW 55, Zehnder controlled residential ventilation, geothermal energy. about 2300-2500 kWh electricity with not too great annual performance factor

At 6000 kWh I would crush everyone into the ground. Botched work by design or what?

Geothermal energy has a higher efficiency, though, right?

A rule of thumb for hot water is 600-800 kWh/person.

I actually underestimated this point back then, I assumed the same guideline value.
The enormous distribution losses in a single-family house are underestimated, even with circulation turned off.
I would rather assume 2500 kWh for 2 people and then 600-800 kWh for each additional person.
In the first year, my circulation ran 24/7 because I didn’t have time yet. 2 people, 4500 kWh for hot water – but from the utility room to the bathroom it is also about 15 m, unfortunately.

That is probably a standard statement from a heating installer just pulled out of thin air. I wouldn't put much stock in it, that's just how things run 'on the construction site' or did he really read through the detailed planning of the energy consultant (which is usually 15-30 pages)? - hardly, why should he. The house is standard size, so it needs standard energy, meaning 1500m3 gas or 5MWh electricity - a bit of buffer, done. Of course, this favors a larger, unnecessary heat pump.

I would react extremely sensitively to that. Behind this exaggerated estimate, there could be massive planning errors that cannot be corrected later.

I would react extremely sensitively to that. Behind this exaggerated estimate, there may be massive planning errors that can no longer be corrected afterwards.

Yes, and unfortunately, 80% of people only deal with the heating system AFTER the house is completed. It used to really not matter, as long as it gets warm.

But geothermal energy has a higher efficiency, right?

Basically yes, ours only has a seasonal performance factor of about 4.3 or so. I don’t have the exact number in mind right now. For example, we don’t have an inverter pump, which is more or less standard nowadays. With a good air-to-water heat pump and a properly planned system, you should also see a 4 in front of the comma or at least come close to it.