Construction costs are currently skyrocketing

I'll throw 'flow 30' into the ring.
Anyone who seriously wants to deal with the topic of energy-efficient heating should consider this principle BEFORE building a house.

[*]Maximum 30 degrees supply temperature in all heating circuits
[*]Maximum 30 mbar pressure loss in the worst heating circuit
[*]Maximum 30% length difference between the shortest and longest heating circuit
[*]Maximum 30% of the heating circuits with individual room controllers
[*]Minimum 30 mm pipe diameter for connecting the heating circuit distributors

regarding construction costs.
Since the 'Ship Shorting crisis' during corona, insulation materials now cost roughly 2-3 times as much. Really crazy.
A roll of clamping felt 032 now sometimes costs 70€, it was available for under 30€ two years ago.

I actually underestimated this point back then, I assumed the same reference value. One underestimates the enormous standby losses in a single-family house, even with deactivated circulation. 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 domestic hot water - but from the utility room to the bathroom it's also about 15 m, unfortunately

I quickly pulled the value from the internet. Of course, it also depends heavily on usage; the value corresponds to about 40 liters of domestic hot water per person per day if I remember correctly. At that amount, the bathtub is no longer usable for bathing. And pipe lengths are naturally another factor. We have both bathrooms stacked on top of each other and the ground floor bathroom right next to the technical room. Only the kitchen has a longer pipe run.

I will email him again regarding this and also have him send me the hydraulic plan and installation plan of the underfloor heating... He said he is using 16x2 with a 10cm installation spacing...

Sorry was short-tempered all day today... ~160sqm according to KFW55, we have central ventilation from Zehnder... The heating engineer said, if I understood him correctly, 6000kwh electricity for heating+hot water... That would probably be about 18000kwh heat... The local heating (biogas waste heat) costs 9 cents/kwh + €416 basic fee until 2031... Operator is a private cooperative... i.e. maximally profit-oriented.

Something doesn't add up, 18000kWh is way too much. We also have local heating from a biogas plant, last year 5800kWh heat energy. This year we currently have 3500kWh, probably then < 5000kWh total. All including hot water. 6.1 cents per kWh with €0 basic fee. 145sqm Kfw40+.

In principle yes, our annual performance factor is "only" around 4.3 or so. I don't have the exact number in my head right now. For example, we don't have an inverter pump, which would be standard nowadays. With a good air-to-water heat pump and a properly planned system, you should also see a 4 before the decimal point or at least come close to it.

Nope. An annual performance factor of 4 is not realistic for an air-to-air heat pump. 3 is already good if you consider a normal winter, not the winters we've had in recent years.

And if I look at the price cap. Gas 12 cents, electricity 40 cents, so a factor of 3.333... the air-to-air heat pump offers you absolutely no advantage compared to a gas heating system. Except currently 12-15,000 EUR higher acquisition costs financed at 4%. Great! ;)

Nope. An annual performance factor of 4 is not realistic for an air-to-air heat pump.
3 is already good if you consider a normal winter, not the winters we’ve had in recent years.

And when I look at the price cap. Gas 12 cents, electricity 40 cents, so factor 3.333... the air-to-air heat pump brings you absolutely nothing compared to the gas heating. Except currently 12-15,000 EUR higher acquisition costs financed at 4%.
Great! ;)

Air-to-water heat pump. Nice try.

Price caps are not a permanent installation and here heat pump electricity costs 16-20 cents (off-peak/peak) and thus is nowhere near a limit. Household electricity 30 cents.

But precisely because of this limited mindset it is good that gas is done in new buildings. In recent years I have experienced dozens of discussions here where similarly shortsighted people with swollen chests planned the great gas heating in new buildings. Now they are all a burden on us. Perfect.