Is underfloor heating in the basement useful??

Hello

we are currently building a new semi-detached house

I am currently considering having underfloor heating installed in the basement.

Our basement has standard normal radiators under the stairs in the utility and storage room.
As a special request, we will (red line) separate the room as an extra room (of course with a door) the two lines at the back of the room will be ventilation slots so that the room can be ventilated because the other two rooms have windows.

The new room is intended to be used as a pantry/storage room and the storage room might possibly be used as a training room

I have a couple of questions:

1: What do you think about equipping the entire basement with underfloor heating? What are the advantages and disadvantages? Extra cost 2700€

2: In the underfloor heating package, the two rooms in the middle (hallway and newly separated room) will have only 1 heating circuit distributor; so the underfloor heating would only heat both rooms with one room controller and the underfloor heating would run under the new wall (calcium silicate wall)

My option would be, for an extra charge, to give the new room its own heating circuit (I do not know the extra charge yet) or to leave out the underfloor heating entirely in that room (then the extra charge of 2700 would of course be reduced) or to let the hallway and the new room in the middle run under one heating circuit

What would you recommend to us?

Since radiators require completely different supply temperatures than underfloor heating, one should definitely not combine both. It also does not save energy to not heat the basement. Because then the ground floor heats the basement and you have to raise the supply temperature.
Therefore, in my opinion, definitely go with underfloor heating and turn it on (e.g., set it to about 18°).
Whether one or two circuits are used depends somewhat on the design of the underfloor heating. Visually estimated at least two. In general, the rule is: circuits should always be similar in length (usually between 80 and 100 meters). If one circuit deviates significantly from this, it is bad for the overall system and must be corrected. Sometimes with insistence.

Thank you for your help

Currently, there are 3 heating circuits. My idea was to split the middle heating circuit into 2 circuits so that I can control the hallway and the new storage room separately.

The standard setup has the middle area fully equipped with underfloor heating. If we have the wall built, the underfloor heating would be under the wall (calcium silicate block). Would that be a problem?

What would you suggest? Should we make 4 circuits out of 3, or should we make the extra room without underfloor heating if it is only a pantry and storage room?

If we leave it out, would there be enough heat coming in so that it doesn’t get moldy and so on?

Thank you for your help

Ah, I hadn't read that quite exactly. So: Three circuits should fit. What definitely won't be done is building a wall ON the heated screed. The screed moves, you don't build on it. You don't even put drywall on it. Therefore, it also won't happen that the underfloor heating is UNDER the wall. For the above reasons (same length of the circuits), I wouldn't separate the hallway and storage room. First supply the hallway, then continue the circuit into the storage room. The latter will then get the slightly cooler water. The combined circuit can be operated about ~2 degrees cooler than the living rooms. Larger differences are not good for efficiency, because then adjacent rooms get "cooled." For the mentioned mold, proper ventilation is also important. Therefore, the basement should also be included in the ventilation concept, especially a storage room where things as well as walls could mold.

how does the circuit then go into the storage room? probably the circuits are connected at the door then, right? I have marked ventilation with 2 red lines there will be a grille so that the storage room (without window) can exchange air with the two adjacent rooms (with window) so it is best to take the standard underfloor heating that the builder offers so 3 circuits 1 technical 1 storage and hallway + storage room right?

Yes, the rooms are usually connected to each other via the door thresholds. There are also the separation strips in the screed, otherwise it would probably crack at these narrow points. The heating pipes should lie on this section inside the protective tube.

And also yes: Three circles, as you described.