Construction costs are currently skyrocketing

You have to specify the region. Between region MD or HAL and M or S, there is often a 20-25% difference at Town & Country. I saw the 152 RE for 183,000 EUR in mid-2019, at the end of 2019 the base price was 189,000.

OWL, but I was only concerned with the development, which should probably be roughly the same percentage-wise in most regions. It does seem to be partly due to higher equipment, but the majority is probably general development after all.

For the heat pump, Town & Country already wanted around 12,000 EUR surcharge in 2019, it is probably 15-20,000 EUR by now. The installer alone would have charged me a 15,000 EUR surcharge if I had switched from gas to heat pump now, without going through the general contractor. But I might get it by Christmas 2024 with some luck.

I am quite alone in this forum with this opinion, but I would still opt for a gas heating system now. Simple technology, energy carrier storable on a large scale, and the distribution network to millions of end customers is available, neither has to be newly built nor upgraded. Just imagine equipping all houses with heat pumps now. I lack the imagination of how the house connections of multi-family houses with 6, 8 or even more units could handle that.

By the way, electricity now costs 48 cents/kWh here (municipal utility price). And I like to say it again and again. The common photovoltaic systems with 5 or 6 kWp, which fit the roofs of "normal" single-family houses, do not even come close to covering the electricity demand of the heat pump in winter. Lots of electricity has to be bought, and in summer the (largely surplus) electricity is fed in at the cheapest rate. Which city villa already has significantly more than 100 m² of roof area, of which, with all the slopes and vents, more than 60 or 70 m² in east, west and south directions are available for photovoltaics?

I am pretty much alone in this forum with this opinion, but even now I would still go for a gas heating system. Simple technology, energy carrier storable in the largest dimensions

Of which we do not have much at home and make ourselves dependent on states whose values do not match our own at all when buying in. Which is also finite and bad for the CO2 targets.

and the distribution network to millions of end customers is available, it neither has to be rebuilt nor upgraded.

Only occasionally patched up when someone has blown holes in it again?

The common photovoltaic systems with 5 or 6 kWp, as they fit on the roofs of "normal" single-family houses, do not even remotely cover the electricity demand of the heat pump in winter.

They don't have to. But they already contribute quite a bit. More than we expected. For quite some time, we had a lousy 4.55 kWp on the roof and an air-water heat pump. Of course, it does not deliver peak amounts in winter, but it does supply some, which should not be underestimated. What many like to forget is that there is still a heating period in spring and autumn, and that was 4-6 months a year during which we achieved excellent synergy effects.

A lot is purchased and in the summer the (largely excess) electricity is fed in at the cheapest rate.

If you can’t use it otherwise. We have luxury home office, so we consumed a lot of photovoltaic electricity ourselves, even in summer. Even those who don't have that do not have a categorically unprofitable system. You can program devices to run over the midday period when you are not at home. With an e-car / possibly a home battery you can get even more out of it. You can heat the domestic hot water higher when there is surplus. There are already intelligent approaches. And even if you feed in – every little bit helps. You have immense influence on the self-consumption rate. Ours was almost twice as high in 2 years as we had calculated (pessimistic-conservative).

You can do a lot, yes. But in the end, it also has to be economical. Sure, anyone who enjoys putting 15kWp on their roof and can afford it. By all means. I have to do some calculations though. And if I end up with a heat pump, geothermal drilling, and photovoltaics costing 40,000+x EUR at the moment... then it won't pay off in the next 20 years...

PS:
Especially since I would have to finance the 40,000 EUR at 5% or more right now, it would be a follow-up financing or even a private loan. Because I don’t have the money lying around.

By the way, electricity now costs 48 cents/kWh here (municipal utilities price).

What does gas cost? You’re quickly in the range of 25-30c/kWh. You can easily beat that with a cheap air-to-water heat pump. Even without geothermal drilling. The latter is done in single-family homes because you indulge in the luxury of a better system, not because you have amortized the additional costs in 100 years.

You have to include the investment costs, not just the pure consumption. As I said, current offer from the installer. Gas boiler out, air-to-water heat pump in, delivery period end of 2024, additional cost around 15,000 EUR. How long does a heat pump last? 15 years? In those 15 years I would have to break even compared to the condensing boiler, so that I come out at zero. I haven’t made a penny in profit yet.

I don’t see that, so it stays with gas.

PS:
And with that, we can close this chapter. I don’t need any more "heat pump is better" sermons. I’ve calculated it, it’s not worth it or barely. Especially since I don’t even have the 15,000 EUR, I would have to finance it.