An experimental approach is used to assess the effect of vegetation on the thermal performance of
a vertical greening system, which comprised of turf-based vertical planting modules, on an elevated
facade wall of a public housing apartment. Despite temperature fluctuations in the various compartments
external and internal to a concrete wall, the vegetated cladding reduced interior temperatures and
delayed the transfer of solar heat, which consequently reduced power consumption in air-conditioning
compared with a building envelope with bare concrete. Vegetation cover led to a different pattern of
temperature fluctuations on wall surfaces, which may affect the comfort of occupants even after sunset.
The cooling effect which was closely associated with the area covered by living plants and moisture in
the growth medium, demonstrated the value of maintaining a healthy vegetation cover beyond visual
amenity. Marked variation in moisture distribution along the vertical profile of the growth medium
highlighted a concern rarely addressed in planting on ground. Substrate moisture measured at randomly
selected locations would underestimate the water stress in some plants and impair their survival.