Benchmarking the performance of building energy management using data envelopment analysis

In traditional methods, benchmarking of building energy performance usually takes into consideration of a wide range of different factors, including floor area, number of occupants, climate condition, energy efficiency of the equipment used, setting of indoor temperature and so on. These different factors are then given different weights to calculate one general indicator. The indicator is “general” as it measures only the overall energy performance of a building. For obtaining more specific information, such as the energy management effectiveness of a building, this paper proposes an adjustment to the traditional approach by using data envelopment analysis. Factors related to the evaluation of building energy performance are divided into scale factors and management factors; the effect of scale factors is then removed to focus on the performance of management factors that may provide an optional indicator to refine the traditional focus on energy consumption per unit floor area. Samples under evaluation incorporate 47 government office buildings in Taiwan, and floor area and the number of occupants are used as the scale factors for climate-adjusted building energy consumption after regression analysis. According to the evaluation focusing on management performance, five evaluated buildings report minimum energy consumption in different scales and they are rated as 100% for the best management performance. Six buildings receive the rating of 80–99%, 23 buildings fall under 60% and the poorest reads 31%. The average indicator of energy performance of all evaluated buildings reads 65%.