Rab Bennetts' concerns about the energy and green claims of Swiss Re (Letters, AJ 13.5.04) could be applied to many 'green' buildings.Massive credibility gaps between the rhetoric and the outcomes are all too common. If we are to make rapid progress towards more sustainable buildings, we need to understand achieved performance (reactivating Stage M in the RIBA Plan of Work), publish the results (come on, AJ! ) and learn rapidly from the experience.
The EC Directive 2002/ 91/EC on the energy performance of buildings - which comes into force in 2006 - will help this on by requiring energy certificates to be available at the points of completion, sale or rental and for public display.
Encouragingly, the ODPM is exploring the possibility that, for non-domestic buildings, certificates required for building regulations purposes might show not just the design ratings, but be updated some three years after handover to include operational ratings based on actual performance (see above illustration for possible format). Such data will be critical to a common understanding - a key purpose of the Usable Buildings Trust, a charity recently set up to promote the more effective use of feedback. Visit www. usable buildings. co. uk for details.
Bill Bordass, William Bordass Associates, London