How complicated are heat pumps in practical operation?

A heat pump is user-friendly and you can rely on it being installed so that you can heat efficiently.

My feeling tells me it is installed in such a way that the homeowner does not freeze; efficiency does not matter to the installer. That is why I fear a multitude of incorrectly adjusted heat pump controls. Experienced this myself with insulators and painters, "it's too warm up here," and quickly valves were turned off at the distributor, and afterwards fully open again, supposedly for balancing.

Just because you don’t drive your car according to the manufacturer’s specifications, you still drive it.

True. But if I had bought a car especially based on the stated values, which as a driver I can never actually achieve, then I feel more like a VW customer after the diesel scandal, even though I can still drive the car afterwards. The problem is not the technology itself, but often the poor or suboptimal installation, which as a private customer I usually cannot foresee or influence. To reassure you: I have NOTHING against a heat pump, I just don’t have one, so I don’t belong to any camp. Seriously, no one can criticize the idea of extracting/using energy from the ambient air or the ground. Nevertheless, other decisions can be made, otherwise it would be as black-and-white as mentioned.

still a thousand times better for the environment than heating with fossil fuels!

And even better is generally heating LITTLE, driving little, etc., to avoid consuming anything in the first place or needing to reduce it. I sometimes find this direction of discussion a bit too flimsy, because I think very few people really want to restrict themselves. Always just as much as comfortably fits into their own life, and so everyone has their own "values."

I would still recommend a gas heating system to anyone who just wants it warm and without hassle. Especially after the discontinuation of new construction subsidies from BAFA and KfW 55EE, the gas price can still rise significantly before a heat pump becomes cost-effective. And electricity prices are currently increasing in many cases, despite the reduction of the EE surcharge. Only the subsidy made the heat pump attractive despite high initial costs. Last year, I still received >10k€ from BAFA, plus 18k€ from KfW55. All of that is now gone.

Of course, there are exceptions like the Panasonic for self-installation, but hardly the average homebuilder would dare to do that. And of course, the standard settings of the heating installer and temperature control with the room thermostats usually mean only 20 to 30% more consumption. Compared to outrageously overpriced maintenance contracts and exorbitant acquisition costs, that actually doesn’t amount to much money. What is more annoying, however, is in the 10% of cases where the additional consumption is 40-100% and/or expensive repairs are soon necessary due to material-wearing poor settings. With gas, you typically avoid all that hassle...

And by the way. I think my heat pump is great, but I consider it more as a technical gadget from which I want to squeeze out another 3% efficiency. Everyone is different...

I would still recommend a gas heating system to anyone who just wants it warm and trouble-free. Especially after the discontinuation of new building subsidies from BAFA and KfW 55EE, the gas price can still rise significantly before the heat pump pays off. And electricity prices are currently rising in many cases, despite the reduction of the EEG surcharge. Only the subsidy made the heat pump attractive despite high acquisition costs. Last year I still received >10k€ from BAFA, plus 18k€ KfW55. That is all gone now.

I would advise anyone who wants no stress and a good, simple solution to consult a reliable planner/installer. However, this applies in general. There are also reports in the forum of houses that have been built on slabs that are too small or skewed roof trusses. Do I then blame the slab or the roof truss? Our heat pump planning, installation, and operation also went completely smoothly without any technical fiddling. OK, good planners/installers are rare... unfortunately, that is true.

Asked because it is always claimed: is a heat pump really more expensive? We paid 10K for quite a luxury unit (modulating Viessmann brine heat pump 333), but we save on the gas boiler, the gas connection, the chimney, and the solar thermal system (which is now mandatory, right?). That adds up to about 10K in total, doesn’t it?

And what might the additional consumption of a standard setting really be? For example, our underfloor heating was designed for 35/28°C and this year it was really cold for a long time here. Yet we end up at only 1,500 kWh heating electricity for 170sqm. Added to that is the pump electricity and, of course, hot water. Let’s say a total of 2,200 kWh. Even if there is still 20% potential (which I don’t believe), that is still less than gas.

As for subsidies, for now we can only wait and see what comes. But it will certainly not be against heat pumps.

I would still advise anyone who just wants it warm and no trouble to go for the gas heating. Especially after the discontinuation of new building subsidies from BAFA and KfW 55EE, the gas price can still rise considerably before the heat pump becomes cost-effective.

I strongly disagree with that! Why? Because you - I assume - will have to build according to the KfW 40 minimum requirement starting sometime next year. Energetically, the heat pump is then a given. And it will be even cheaper than it already is now.

With gas, you typically save yourself all the trouble...

...except for the annual mandatory maintenance and chimney sweep for gas.

Only the subsidy made the heat pump attractive despite the high acquisition costs.

Define high acquisition costs. The heat pump alone starts at €3,000 and depending on the model and manufacturer is open-ended upwards. In return, no chimney and no gas connection. In the end, it may not add up, but compared to gas, a heat pump is not "expensive" - excluding brine heat pumps.