The effect of air-conditioner operation modes on the energy-saving capacity of external wall insulation in residential buildings

In this study, subjective questionnaires and a building energy simulation were utilized to investigate the impact of air conditioner operation on the energy consumption/savings of a model building with different types of exterior wall thermal insulation. The results indicate that an intermittent energy usage mode is generally used in residential buildings in hot summer and cold winter areas. Air conditioner operation behavior is affected by the human thermal experience. The greater the indoor temperature deviates from the human comfort range, the higher the air conditioner operation frequency. Under continuous energy usage mode, the annual heating and cooling effect of the exterior thermal insulation was found to be better than that of interior thermal insulation. Under the intermittent energy usage mode without considering residents’ temperature tolerance, the annual heating and cooling effect of the interior thermal insulation was better than that of the exterior insulation. Under the intermittent energy usage mode considering tolerance levels, the energy-saving effect of the interior and exterior thermal insulation of the exterior wall was different. In the case of low and medium temperature tolerance, the annual heating and cooling energy-saving effect of the interior thermal insulation was better than the exterior thermal insulation; in the case of high tolerance, the heating and cooling energy saving effect of the exterior thermal insulation was better.