The children's room is too warm in the new building.

Is it too cold anywhere? If not, lower it slightly again and wait another 24 hours

Is it too cold anywhere? If not, lower it slightly again and wait another 24 hours

In the guest bathroom, the temperature does not rise above 21 degrees even though the floor is noticeably warm. However, I suspect that cold air is flowing into the room through the Lunos ventilation.

Does the bathroom only have underfloor heating?

It might come from the ventilation. But that doesn’t help. Is the valve in the bathroom fully open?

The temperature in the guest WC does not go above 21 degrees even though the floor is noticeably warm. However, I suspect that cold air is flowing into the room through the Lunos ventilation.

Maybe your guest WC is the room that determines the supply temperature. Makes sense, because there is only a small heating surface available. You could heat the surrounding rooms more strongly if they are significantly cooler: hallway, utility room, or whatever you have there. If the supply temperature could be lowered significantly without the guest WC, then you have to consider how important 21 instead of, for example, 20° is there. When adjusting, it is better to open the circuits of the cold rooms rather than throttling the circuits that are too warm, so that a high overall flow is possible.

Or the area is simply not sufficient to heat the room more effectively. If the flow is turned up fully, your only options are to increase the flow temperature overall or to accept it.

The temperature in the guest WC does not rise above 21 degrees

I don't know how lengthy your sessions in the guest WC are, but I think 21 degrees is warm enough and wouldn't worry about this room.