## 1 Introduction
### Scientific Studies Using the Building Energy Simulation Method  
The issues related to window-to-wall ratio (WWR) were considered in detail by [PERSON] et al. [1]. The aim of this analysis was to assess the impact of different levels of WWR on the environment, economic indicators and occupant satisfaction metrics. For this purpose, the authors used the triple bottom line (TBL) method [2], performed energy simulations using EnergyPlus v. 8.9 software and estimated the net present value (NPV), the life cycle costing (LCC) and the life cycle assessment (LCA). A 12-storey office building located in different climatic zones of the USA represented by San Francisco, Boston and Miami was an example research object. Energy simulations and economic calculations were performed, assuming a 60-year lifespan for the building and the replacement of windows after 40 years. The general conclusion that emerged from the analysis was that an increase in the WWR coefficient increases the environmental impact and life cycle costs. In addition, the results showed an increase in occupant dissatisfaction in all three climate zones. A multi-variant analysis of glazing selection was performed by [PERSON] and [PERSON] [3]. A single-family building with an area of 154 m\({}^{2}\), located in Jordan and Germany, was analysed using TRNSYS software. The heat transfer coefficients of single-, double- and triple-glazed windows and climatic conditions, as well as the area and orientation of the glazing, were used as variables in multi-aspect energy simulations. The results of the calculation of the annual energy consumption costs for the heating and cooling of the reference building indicated that, in the optimal variant, the savings amounted to 21% for the climatic conditions of Amman, 20% for the location in Aqaba and 24% for Berlin. [PERSON] and [PERSON] [4] performed a multi-criteria analysis of a reference residential building located in Toronto (Canada). The aim of this study was to minimise the life cycle costs of the case study house. The authors developed an energy model of this building in EnergyPlus software and then validated it based on actual energy consumption. Double, triple and quadruple glazing packages were considered in this study. It turned out that energy consumption can be reduced by up to 33% compared to the current energy efficiency requirements contained in the building code. A study of the influence of large glazing areas in buildings in hot climate zones on the increase in solar heat gains and cooling loads was carried out by [PERSON] et al. [5]. Three types (passive, active and BIPV) of high-performance glazing systems were analysed as an alternative to traditional double-glazed windows in a seven-storey office building located in New Cairo (Egypt). Energy consumption costs for multiple options were estimated based on energy simulations performed in DesignBuilder software. As a result of the economic analysis, it turned out that glass with a metal oxide layer (Low-E) was the most effective, because the Payback Period (PBP) was the shortest and amounted to 15 years. Low-E glazing also had the highest NPV and the lowest LCC, primarily due to low disposal costs. The electrochromic glazing system, on the other hand, had the highest LCC value and a thirty-year Payback Period, which made it economically unprofitable. [PERSON] et al. [6] determined the parameters allowing for the optimal selection of a building glazing system. Based on the life cycle assessment, an assessment of the impact of the window characteristics on the environment, this study was carried out. In addition, investment costs were estimated and already taken into account at the building design stage. Unlike in previous studies, the entire building was not considered. Only a room [7] with an area of 5.50 m \(\times\) 3.60 m and a height of 2.80 m was taken as a case study.