Save as You Pay - or not?

When retrofitting commercial and domestic property, funding the capital investment needed to make existing buildings energy efficient is a challenge, as payback from the value of energy savings can be of the order of decades.

Pay as You Save Schemes are partly accepted in the commercial and domestic sectors, where bank schemes and the government Green Deal are on offer. One of the issues is the certainty of payback (or the lack of it) in the budgeted time scale.

Several factors are associated with this uncertainty; the quality of the materials and components used in the retrofit, the skills levels of the retrofitting workforce and the behaviour of the occupants of the building after it is renovated.

Last but not least, knowledge of the energy performance of the building before, as well as after the work is done is obviously vital to see the improvement achieved, and hence the payback.

Given the criticality of achieving predicted energy savings in order to create an acceptable investment model for fund providers, a precise science of ‘investment-quality energy auditing’ is required.

An understanding of how behaviour is affected by design and engineering is also vital. Precise energy auditing requires knowledge of materials and component performance, good retrofitting practice, and monitoring, logging and analysis techniques.

A collaboration to look at this type of energy auditing package has recently started between Arup, University College London (UCL) and the National Physical Laboratory (NPL). The organisations have complementary capabilities to measure, design and monitor the built environment.

Work is also progressing to look at how design, architecture and engineering in buildings relate to behavioural outcomes. Energy performance, well-being and productivity are particular focus points.

This initiative is being sponsored by Arup, The Royal Academy of Engineering, RIBA, the Economic and Social Research Council and four government departments. The output will be guidance notes for policy-makers and researchers.

Jeremy Watson is director science & technology at Arup