COOLING OF A SOUTH-FACING WALL USING A DOUBLE-SKIN GREEN FAÇADE IN A TEMPERATE CLIMATE^©

Green façades made of metal wire screens and mounted to the walls of buildings to support trellised vegetation is increasingly looked to as a means of urban greening and as a sustainable building technology. Here we examine the thermal cooling performance of three candidate vine species (hops, Virginia creeper, and riverbank grape) on a 3-dimensional welded wire frame against a south-facing wall in a temperate climate. We found that from May to September, the green façades kept the wall surface on average 1.84°C (3.31°F) cooler, with grape as the best performer reducing surface temperatures by 2.91°C (5.24°F) in September. In all three species, wall cooling increased with vegetated cover, which increased over the growing season. The effect of vegetated cover on wall cooling was most apparent in hops which re-grows from root stock and basal stems to cover much of the trellis by the end of the growing season, whereas grape and creeper foliage re-grows from stems that remain attached to the trellis, achieving more heterogeneous covering earlier in the growing season. These findings contribute to a growing body of research on green façades and their functional performance as components of the building envelope and as architectural materials.