Energy-led refurbishment of non-domestic buildings: ranking measures by attributes

In the context of the energy-led refurbishment of traditionally constructed non-domestic buildings, the purpose of this study was to identify the attributes that professionals consider to be important in the selection of energy performance improvement measures (EPIMs) and to establish their relative importance.

A questionnaire-based Delphi exercise was carried out to draw up a set of attributes agreed among a small panel of experts. Subsequently, a paired comparison questionnaire was completed by the experts to establish the relative importance ascribed to the attributes.

In total, 22 assessment attributes, relevant to different stages in the building’s life cycle, were agreed as important by the expert panel. Measures fell into one of three broad groups, expressed on a weighting scale of 0-100, such that the sum of the weights of all 22 measures was 100. Measures of relatively high importance (7-9 per cent) included capital cost, potential energy and carbon savings, financial payback and impact on the building’s vapor permeability. Measures of medium importance (4-5 per cent) were impact on 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 per cent).

This paper is the first attempt to draw up a ranking order of the attributes of EPIMs applicable to non-domestic buildings. It confirms that more attributes must be considered by professionals with decision-making responsibility than merely cost, energy performance and payback on investment and suggests that policy instruments targeting or incentivizing a single or a restricted range of attributes risk failure to deliver the desired improvements.