Effect of roof types on energy use in residential buildings in cold climates

The role of residential building envelope components is significant in terms of supporting a structure and transferring associated loads, providing aesthetic appearance, and controlling the flows of matters and energy. The control function is particularly important in terms of energy use as poorly designed and constructed envelopes can negatively affect the overall performance of a building. Among others, roofs play a critical role due to their area of coverage, direct interaction with precipitation, and a significant share of total heat transfer. This is especially true in case buildings located in countries with cold climate conditions. This study aimed to investigate the impacts of different roof types on the energy use of residential buildings in Nur-Sultan city, Kazakhstan. Moreover, it aimed at performing a cost analysis to compare the four roof types. The building models with roof types such as flat roof, green roof and gable roof with finished and unfinished attics were simulated and compared in terms of their energy use. The findings indicate that the most energy and cost efficient two-storey building has gable roof with finished attic. The green roof is the most energy efficient choice for a one-storey building. It consumes 4.5% less energy and will pay off in 9 years