Heating individual rooms with ventilation

Hello,

I have a general question about ventilation systems. We are planning the construction of a single-family house with approximately 190m². On the ground floor, a conventional underfloor heating system is to be installed. Since the building design is very open, no underfloor heating is actually planned for the upper floor (92m²) – heat rises upwards. This makes heating the rooms on the upper floor naturally very sluggish. However, since the house is very well insulated, little heat is lost to the outside. If it should still be necessary to heat one of the rooms on the upper floor independently and quickly, there is the possibility of doing so via the ventilation system – therefore my questions:

I have read about electric reheaters that are installed directly in the ventilation duct of the respective room. How useful are these? Heating directly with electricity is not very economical… Who offers such products?

Are there ventilation solutions in which heat exchangers are installed in the ventilation ducts of the individual rooms, supplied by the actual heating system (gas condensing boiler)? Who offers such solutions? Or is this not done because of the effort involved?

Thank you for the answers

....I have a general question about ventilation systems. We are planning the construction of a single-family house with approximately 190m². On the ground floor, a conventional underfloor heating system is to be installed.

What about the upper floor?

....Since the construction is very open, an underfloor heating system is actually not supposed to be installed on the upper floor (92m²) – heat rises upwards.

Who announced that? ;-)

...If it should still be necessary to heat one of the rooms on the upper floor independently and quickly, there is the option via the ventilation system –

How should that be possible?

...Are there ventilation solutions where heat exchangers are installed in the ventilation shafts of the individual rooms, which are supplied by the actual heating system (gas condensing boiler)?

Just consider what capacity "air" can actually provide in conventional ventilation systems! ;-)
Apparently, there is no MEP planner here! ;-)

Best regards