Energy efficiency of buildings: simple appraisal method.

A new method is proposed to appraise the relative energy efficiency of designs for new or refurbished buildings. Based on the development of an energy efficiency index, it is simple to use and understand, and requires no particular expertise. The method offers a straightforward determination of likely energy performance. It addresses the total power rating of plant installed to achieve specified indoor environmental conditions, and the monitoring and control equipment which manages that capacity. Potential applications include appraising performance against established or proposed standards of good practice, testing compliance with energy performance specifications and ranking alternative design choices, either overall or at various stages of design. Inverted, the method offers targets for plant sizing. The strategy offers services designers a more authoritative argument for plant room space early in the design. Despite its simplicity the method promises good field performance. Limited data from six fully air-conditioned buildings reveal a perhaps surprisingly good correlation between the energy efficiency index and observed performance. Once performance data for a wider range of buildings are available, the method can be developed fully for widespread practical application.