Selection criteria for energy performance improvement measures in traditionally constructed non-domestic buildings

In the context of the energy-led refurbishment of traditionally-constructed non-domestic buildings, a two-stage Delphi exercise has been carried out in order to identify the criteria that professionals consider to be important in the selection of energy performance improvement measures, and to establish their relative importance. Based on the opinions of a panel of experts, 22 assessment criteria were identified, covering short-term outcomes, long-term issues, end of life issues, and whole life impacts. A paired comparison survey enabled the weightings of relative importance for the criteria to be determined. Measures fell into one of three broad groups, expressed on a scale of 0-100, such that the sum of the weights of all 22 measures was 100. Measures of relatively high importance (8±1%) included capital cost, potential energy and carbon savings, financial payback and impact on the building’s vapour permeability. Measures of medium importance (4.5±1%) were impact in internal air movement, loss of significant original building fabric, impact on internal layout, appearance and occupant comfort, environmental impact and availability of grants or subsidies. Eight further measures were ranked of low importance (2-3%).