Investigating the simultaneous effects of building orientation and thermal insulation on heating and cooling loads in different climate zones

This paper investigates the simultaneous effect of orientation and thermal insulation of the building on each other and on the heating and cooling loads of buildings. For this aim, the heating and cooling loads of a sample building are calculated with different orientations and amounts of thermal insulation in multiple cities in Iran, which have different climatic conditions. The optimum building orientation in all the surveyed cities is when the main façade faces south, which can reduce the energy consumption of the building by 11–39%. This reduction was greater in cities with higher cooling-degree-days (CDD); which means the effect of orientation on the cooling load of a building is more significant than its effect on the heating load. Increasing the thermal insulation of the exterior walls also reduced the energy consumption of the building. 5–10% reduction in total energy consumption of the building was observed by decreasing the u-value of external walls from 0.8 to 0.4 W/m2K. This reduction was higher in cities with higher heating-degree-days (HDD) which means that the effect of insulation on heating energy consumption is more significant than its effect on cooling energy consumption. In addition, the results indicate that the building orientation and thermal insulation improve each other’s efficiency. Highlights The effect of building orientation on energy consumption was investigated. Building envelope insulation effect on heating and cooling demands was investigated. The simultaneous effect of building orientation and insulation was analyzed. The results were discussed concerning different climates and climatic conditions.