During summer, or in hot climates, air inlets and outlets are opened as to promote the stack effect (hot air rises) thus renewing hot air within the cavity, released at the top of the cavity, with fresh air from the lower regions of the cavity. Within the air cavity, sun shades can be used to absorb and reflect solar heat energy which coincidently promotes an even higher temperature differential for the stack effect to take place within the cavity. As a result, cooling cost for inhabited areas are dramatically reduced with human comfort factors increased for areas within close vicinity of the façade.
With the subsequent use of passive circulation and insulating properties of air for summer and winter conditions, the heating / cooling energy saved is close to 50% when compared with a standard single layer curtain wall. In most cases, the system does not require mechanical equipment and as such no energy and very little maintenance cost is associated with a double skin façade system.
