The architect's decision to select a glass type for a high rise building has significant impact on both the initial and the running cost of a building. This is particularly the case with many of the new buildings that have a high window-to- wall ratio (WWR). While several competing factors impact the architect's decision, this study supports such a decision for buildings in the United Arab Emirates (UAE) by focusing on the relationship between the glass thermal characteristics and its cost. At this stage of the study, it uses a typical 30 story residential building with a WWR of 50% and a north-south orientation. An energy simulation modelling tool is used to provide data on the impact of different types of glass on the cooling load and hence the energy consumption. The cost and thermal properties of used glass types are those that actually exist in the market of the UAE. The study considers the different energy price structure in different parts of the country. Using both the simple payback period and the life cycle cost reduction techniques, optimal glass thermal properties are identified.