skip to content



Construction works have just commenced on a new building for the Department of Engineering (entrance façade pictured) located on the West Cambridge site.  As part of the brief, the late Professor Sir David Mackay came up with the concept of an Energy Cost Metric.  This Metric has been developed as a tool for integrating low energy objectives into the design process alongside capital cost.  The energy required to manufacture and deliver the construction materials has been considered, as well as the energy that is predicted to be consumed during building operation.

The Energy Cost Metric discourages ‘green bling’; an addition that may be seen as sustainable but do not deliver in the long term, and promotes a more rigorous ranking of the most cost effective measures for minimising energy use. 

The Metric has been used throughout the design process; for instance it informed a decision to use a steel frame instead of in-situ concrete.  The decision to use a ground source heat pump to efficiently cool and heat the building also scored well using the Energy Cost Metric; installing a heat pump means that the project does not require a natural gas supply. 

The Metric has now been adopted by the Contractor (SDC) and is informing final specifications; for example in defining the optimal thickness of wall insulation.

Feedback from application of the Energy Cost Metric to a real project will form a useful strand of research for the Engineering Department and it is hoped that the idea will be developed and applied to the design of future buildings and refurbishments.