Is underfloor heating in the basement useful??

So basically, is right, I think. However, it might be that he is going a bit overboard. Not everyone can and wants to get that deep into the topic. Especially in the basement, an ERR can make sense. There, you can turn it down a bit or even off completely if the rooms are not used for a longer time.

Not everyone can and wants to dig that deep into the topic.

Two evenings using the search engine of your choice. After 10 minutes there are step-by-step instructions. But that wasn’t what I wanted. I wanted to get the heating engineer to do his job so that you don’t pour thousands of euros down the drain... My suggestion was the minimal method. But everyone has to decide for themselves.

Especially in the basement an ERR can make sense. There you can turn it down a bit...

There is nothing against setting a few degrees lower in the basement. You don’t need an ERR for that. The heating circuit is throttled by half a liter. You can tell the heating engineer right away, then you don’t even have to turn the dial yourself.

... or completely off if you don’t use the rooms for a long time.

I think we already discussed that at the beginning of the thread.

How do the individual room controllers actually work? Do the individual room controllers regulate it by turning up to 100% until the target temperature is reached and then turn down to 0%?

Or do they regulate cautiously in small steps?

Normally the former. So normally you have thermoelectric drives that are operated in an on/off mode.

Hello, we have received the offer for our special requests

The following is stated in the FHB

Underfloor heating instead of radiator heating in the basement. 1 € 2,960.00 € 2,960.00  with thermostatic settings planned for cellar purposes;  a heat load calculation is not part of this offer;  setting the location of the (enlarged) underfloor heating distributor;  room-thermostatic control.

Can you help me again

How can we help? Price estimate? I'm too lazy to look it up, but if there were radiators before, I find it quite expensive. The effort for radiators is not much less, the material costs are even higher. But what can you do... It would definitely be worth the extra cost for me. The additional floor space alone makes up for it.