Ultra-Low Thermal Transfer
Along with glazing, a high-performance envelope provided by deep overhang over the south façade, external shading fins in the north facade, heat minimized east and west facades/windows, and shaded and insulated roof, all contribute to the ultra-low overall thermal transfer value (OTTV) of 11 W/m2 (over 80% lower than the maximum value required under the current statutory control).
OTTV is the quantity of heat transferred per unit of temperature difference into a building through its walls or roof, due to solar heat gain and outdoor indoor temperature difference. The lower the OTTV of a building, the higher would be the building energy efficiency.