The window to wall ratio for high-rise office buildings in a temperate climate: assessing façade embodied energy and building operative energy (life cycle energy) in London

Building energy demand starts from its construction stage to its demolition stage. A significant factor in the life cycle of buildings is the embodied energy (EE) as it directly relates to the overall sustainability of the built environment (Treloar, 1994). It is desirable to identify aspects, which consume significant amounts of energyand develop appropriate strategies to reduce it. In office buildings, life cycle energy (LCE) range between 250-550 kwh/m2 per year at which the EE represents between 10 to 20 % of the total LCE consumption, while operative energy OE represents the outstanding 80-90% (Ramesha, et al ., 2010). Each building is a compound combination of a variety of processed materials, which contribute towards the EE of the buildings and the overall building CO2 emissions (Langdon, 2008). This study proposes a feasible approach to minimise EE and OE with a main purpose to reduce the building life cycle energy by investigating the ideal window to wall ratio in high-rise office building typology. The aim of this study is to determine the significance of optimising window to wall ratio for high-rise office buildings in a temperate climate through assessing the building envelope EE as well as calculating the BOE (life cycle energy).