An analysis of energy efficiency actions within a portfolio of existing commercial office buildings
Authors: Roussac, A. Craig
This paper presents preliminary findings from a retrospective analysis of energy efficiency actions undertaken in eleven large commercial office buildings between 1 January 2004 and 31 December 2008. The sample buildings were selected from a single portfolio that accounts for five percent of Australia’s commercial office accommodation. Collectively they represent 1.4 percent of the entire Australian CBD office market.
Investments in technologies and non-technological initiatives were evaluated for their effectiveness, in both energy and financial terms. Occupant comfort, as expressed by ‘hot/cold complaints’ registered with a tenant helpdesk, was also analysed.
The results of this analysis show that energy use intensity (MJ/m2 per year) reduced by 29 percent across the sample buildings over four years. Technology and management initiatives appear to have been equally important contributors to the reductions in energy use. In addition, a positive relationship between a building’s energy performance and the number of complaints by occupants about ‘hot’ or ‘cold’ temperatures was established from the data: as the buildings’ energy efficiency improved, the occupants’ apparent dissatisfaction or discomfort levels decreased.
These preliminary findings are significant and suggest there may be scope to ‘fast track’ energy efficiency within existing commercial office buildings while achieving positive consequences for occupant comfort and strong financial returns.