Occupant Behaviour and Direct Rebound Effect in Commercial Building Energy Retrofits

Abstract

Energy retrofits have been implemented as a measure to counter increasing energy consumption worldwide. However, this improvement in energy efficiency does not always translate into achieving the full expected energy savings due to rebound effect. Rebound effect is the offset or take- back of expected energy savings due to varying occupants’ behaviour and response to efficiency gains. In commercial buildings, energy consumption is very high especially in the area of space cooling. Hence, it is important to estimate the magnitude of rebound effect to find out its significance. Presently, there is a lack of comprehensive studies done on measuring rebound effect and there is not yet one done in Singapore.

This study adopted 3 calculation methods, namely – direct measurement, direct estimation and implied rebound effect in the calculation of direct rebound effect in chiller retrofits in 4 commercial buildings. Varying rebound effect across the 4 buildings was calculated and reasons had been suggested to justify for such differences. Magnitudes of rebound effect calculated for Buildings A to D were -34.29%, 1.70%, 40.90% and -8.39% respectively. There was no “back-fire” effect which suggested that energy retrofitting did reduce energy consumption.

Realizing the magnitude and effects of rebound effect in retrofits help buildings which want to engage in retrofits and ESCOs to reflect the true energy savings that can be achieved. Hence, more efforts and research need to be conducted in Singapore to study the significance of rebound effect as well as in the design of energy policies.