It is possible in theory to install parquet floating on underfloor heating, but don’t do it. We definitely recommend a fully glued-down installation.
Thermal efficiency is much better with a fully glued-down installation. This is because with a floating installation, there is a layer of air between the screed and the floor, and air insulates.
Moreover, wood expands under the influence of heat and air humidity. With underfloor heating, the floor is even more sensitive to this. By gluing down the parquet using a parquet adhesive suitable for underfloor heating, you can limit expansion and contraction. This reduces the risk of gap formation. Nevertheless, this can never be entirely ruled out with underfloor heating.