first principle calculation of boiling point of water?

The boiling point (i.e. the saturated vapor pressure as a function of temperature) is described by the Clausius–Clapeyron equation which is a consequence of classical thermodynamics. Of course if we start investigating why certain thermodynamic potentials used in that equation have to be such and such then eventually we'll need quantum physics to explain the size of atoms and molecules. But there are more direct commonly observed macroscopic consequences of quantum physics which include photovoltaics, lasers, superconductivity. These seem to be closer to what you are looking for.