Determination of Optimum Energy-Economic Insulation Thickness for Building Walls in Climate Zones of Iran

Document Type : Original Article


Department of Mechanical Engineering, South Branch, Islamic Azad University, Tehran, Iran


The major areas of energy consumption in buildings are heating, ventilation, and air conditioning. Applying thermal insulation in exterior building walls is one of the most effective and efficient methods to reduce energy consumption. It is highly recommended to optimize the walls insulation thickness in order to minimize total investment costs. In this study, numerical investigation is conducted in order to compute annual heating and cooling loads of a modelled building in Iran climate zones such as Tehran, Tabriz, and Bandar Abbas. Insulation materials including elastomeric, polyurethane, stone wool and glass wool with different thermal conductivities and costs are applied as one of the external wall layers. The main purpose of this paper is to obtain the optimum energy-economic insulation thickness based on total costs of insulation and energy over a lifetime of 20 years. The analysis of energy savings and payback periods are also evaluated in this research. Results indicate that optimum insulation thickness varies from 0.79 cm to 11.39 cm. It is evaluated that glass wool is the most optimal insulation in aspect of reducing total costs. Energy saving analysis demonstrates that polyurethane is the most efficient thermal insulation among other studied materials. Elastomeric, stone wool, and glass wool are placed in next positions, respectively.


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Volume 2, Issue 2 - Serial Number 4
September 2023
Pages 185-204
  • Receive Date: 07 August 2023
  • Revise Date: 10 August 2023
  • Accept Date: 12 August 2023