Is underfloor heating in the basement useful??

Please describe your heating system. I'm sure we can find something to improve together. ;-)

But of course the OP has the opportunity and even the obligation to listen to all opinions here and then continue researching independently. There are plenty of scientific papers, especially for heat pump systems and well-insulated buildings, on how it should be done and what simply does not work. We are only providing a summary of the state of the science here.

what exactly triggered you? Which of the mentioned errors have you had installed in your system?

Well, the concept was set up by the developer. The heating engineer is just the executing subcontractor here who just puts on a brave face. But the client and paying partner in this case is the developer, and what they want is what gets done, even if there are better solutions. But even the average heating engineer in a single-family house doesn't necessarily have an interest in installing the most efficient heating system for you. That usually means extra effort, which he doesn't always get paid for. He also doesn't have the time or desire to come by for 5 minutes every two days over one to two weeks for a thermal balancing. Therefore, what's often installed is what works, causes as few warranty claims and follow-up visits as possible, and is inexpensive so that the customer also awards the contract. Of course, there is also the brand Heizi, which considers itself the ultimate authority and simply does not accept other expert opinions. Mind you, much of what is posted here by laypeople was not invented or cobbled together by them but extensively discussed in relevant forums by experts and also planned, among others, by engineers. Does local/district heating or a gas boiler work in the sense that it heats? Sure! Is it medium- to long-term one of the most efficient systems that should be installed in a single-family house? In my opinion, no.

...Does district heating or a gas boiler work in the sense that it produces heat? Sure! Is it medium to long term one of the most efficient systems that should be installed in single-family houses? In my opinion , no.

no contradiction!

Nevertheless: one of the most efficient systems is a political discussion.

Because energy prices are politically determined.

does efficient mean lucrative?

In France, electricity prices are relatively low because EDF’s nuclear power-based electricity is subsidized. (That’s why there are proportionally many direct electric heating systems there.) And that came about because the entire nuclear technology chain was needed for the atomic bomb construction.

Is it efficient because of that?

Gas prices have more than doubled in recent months. Is gas still efficient, although the doubling is purely politically determined?

Gas supply is supposed to increasingly switch to a higher hydrogen blend (currently about 10% hydrogen content). Does that make gas heating more efficient or less efficient? Ecologically, that certainly makes sense!? Also because the efficiency of direct hydrogen gas heating is better than the detour via an indirect electric heating.

That is to say: cost minimization can only be pragmatically used for efficiency assessment. However, supposedly "better efficiency" does not necessarily have to be sensible.

Nevertheless:
one of the most efficient systems
is a political discussion.

Efficient is what produces a lot of heat with little energy. Currently, that would be the heat pump, then a long time nothing. Efficiency has nothing to do with costs.

In France, electricity prices are relatively low because of the nuclear power-based ...
Is it efficient because of that?

Of course not. No one claimed that either.

Is gas still efficient, even though the doubling is purely politically determined?

No. But it never was...

The gas supply is to be increasingly switched to higher H-blending

Also because the efficiency is better in direct H-gas heating than the detour via
an E-indirect heating.

Hydrogen will never arrive in private homes. No one can afford that. Therefore, the question is pointless.

Meaning:
cost minimization can only pragmatically be used to assess efficiency.
Supposedly "better efficiency" does not have to be sensible.

Costs still have nothing to do with the efficiency of a heating system. Higher efficiency is sensible above all for the preservation of our habitat.

Yes, I meant purely energetically.