[jaclaz]

A well insulated house needs some sort of mechanical ventilationm otherwise you will have problems with humidity and - in worst cases - mould.

The ventilating units are usually placed in the basement and are not noisy (but need some maintenance and cleaning).

There are heat pumps that simply heat water and are suitable for underfloor heating, no fans.

Underfloor heating is usually "slower" (compared to air heating) but works just fine, actually better.