It has already been understood and accepted that the ‘ventilated façade’ is a re-interpretation of the ‘rain screen façade’ where the main role of the external layer and ventilated cavity is to provide energy saving, rather than just water tightness.

Now we should take a step back and take a specific view of the solution. In terms of saving energy, this construction solution projects shadow onto the inner wall which encloses the interior space. In other words, this blocks the direct sunshine from heating the envelope which encloses the habitable space.

However, is a double-skin system with a ventilated cavity actually necessary to achieve this? The answer is no, all that is required is to provide solar protection. In fact, solar protection and air movement. As long as this air movement does not depend on the buoyancy effect its temperature would not have to rise that much. Louvers, awnings or even the foliage of a dense tree can achieve a same, or maybe better result than an outer layer and a cavity. It would of course be another matter if the system was intended to have the double function of providing drainage as well as saving energy.

In this website, we have already mentioned examples of strategies where shadow is projected onto a façade by means of an additional skin, which is neither hermetically sealed, nor used for drainage purposes: