The aim of this paper is to interrogate the principle of heat gain by the Overall Thermal Transfer Value
(OTTV) through residential building facades. This study proposes three façade configurations as case
studies to determine their capability of achieving the OTTV set by the current residential standards.
Utilising the OTTV formula provided by the Malaysian Standards, the OTTV of each case study was
calculated using parameters including Window-to-Wall Ratio (WWR), Shading Coefficient (SC), U-values
and solar absorption (α). Results showed that each of the façade generated OTTV exceeding the regulation
of 50 Wm-2. The study uncovered the increase in WWR leading to the increase in OTTV. The OTTV
increased alongside window areas due primarily to the high amount of heat gained through windows,
a constituent component of OTTV. Simultaneously, high Shading Coefficient (SC) and U-values were
found to cause the high amount of solar heat gained through windows. The result underpins the impacts
of high solar heat gain particularly from windows of a building envelope on OTTV. Recommendations
for improvement of OTTV of the residential façades are also discussed..