Does it heat well? Even in winter?

This is actually one of its greatest advantages: it provides gentle, constant, and enveloping heat, which does not depend on ambient air like electric baseboards or forced-air systems.

Why does it heat up so much?

• Heat is distributed from the bottom up, where you need it: your feet, your body, your living space. No cold drafts on the floor.
• The system operates over a large surface area, allowing the room to be heated evenly, without cold spots.
• It maintains good thermal inertia: once the floor is warm, it continues to radiate heat for several hours, even if the boiler or heat pump temporarily shuts down.

And in the middle of winter?

Yes, even when it's -20 or -30°C outside, a well-designed system (with good insulation and a suitable energy source) is more than capable of keeping the house comfortable. Of course, the system must be sized correctly for the house, taking into account the local climate and building materials.