UFH does not promote heat low down. Hot air rises. When the heat emitter
is
the floor, when the hot air moves from the emitter to the top of the room
it
passes you, heating you along the way.

It is because the evenly heated air rises only slowly with underfloor
heating. Basically, the evenly heated hot air is slightly constrained from
its upward trajectory by the evenly cold air trying to fall above it. The
reduced air flow leads to lower losses.

In the event that you have point heating, (i.e. an unforced convector), the
hot air is hotter than nearby air and rises more quickly, leading to greater
vertical air currents from the convection and a more rapid heating of the
ceiling. Normally, this is desired, at it heats the bulk of the air more
quickly and even the high up heat is desirable.

Another advantage of the underfloor heating in this situation is the larger
area of the radiator, leading to more pleasant radiant heat, which can
result in similar comfort levels at a lower actual temperature.

Christian.