Heat Loss Optimization of a Building with Different Window to Wall Area Ratios

KOYUN T., Koc E., AKÇAY İ. H., Kent E. F.

Journal of Testing and Evaluation, vol.52, no.2, 2024 (SCI-Expanded) identifier

  • Publication Type: Article / Article
  • Volume: 52 Issue: 2
  • Publication Date: 2024
  • Doi Number: 10.1520/jte20230124
  • Journal Name: Journal of Testing and Evaluation
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Applied Science & Technology Source, Compendex, Computer & Applied Sciences, INSPEC
  • Keywords: glass type, heat loss, hot-humid climate, optimization, window/wall area ratio
  • Istanbul Technical University Affiliated: Yes


The types of glass and exterior walls and the window-to-wall ratio (WWR) on building façades play a major role in heat losses that occur in every type of building, residential or commercial. The opaque and transparent surfaces of buildings have an important role in terms of both energy losses and energy gains. Windows are the parts of the building envelope where heat losses mostly occur. As the WWR increases on the façades of a building, heat losses increase, but heat gains from solar energy also increase, which assists in free heating of the building. In this study, a detached residential building located in Antalya, Turkey, a province with hot-humid climatic conditions, has been examined. A series of simulations were carried out to detect the effects of WWRs and different glass, frame, and exterior wall types on heat losses of the building. The heat loss values obtained from these simulations were processed by using a special mechanical installation calculation software. Simulations were performed for apartment rooms with levels of WWR ranging from 30 to 60 % of the wall areas facing the façade. In order to minimize heat loss, double-pane glass (or double-glazed glass) was used instead of singlepane glass. The aim of this study was to find the optimum value in terms of applicability and economy. The optimum value was calculated by minimization according to both the linear graphical method and the dual simplex optimization method. The values found in both methods were compared and interpreted. It is believed that the optimized glass, frame, joinery, and exterior wall parameters, which are influential to the energy performance of the building, will make a positive contribution to the architectural design phase in addition to improving the energy efficiency of existing buildings.