The sliding scales of energy efficiency

Greenwich Council likes to tubthump about its own "success", and it's "energy efficiency" ratings are no exception. In a press release last Friday they made much about having some of the "most energy efficient" homes in London. The cause for this celebration was a whopping 2 point increase in the Council's average SAP rating (Standard Assessment Procedure) to 69 points on the 120 point scale.

SAP ratings are the Government's recommended system for measuring home energy efficiency. It's essentially the energy cost rating of a property, and is calculated against space and water heating. The system's based on something called "SAP2001" and has a scale which starts at 1 (poor) and goes up to 120 (excellent).

The average SAP2001 rating across the country was between 80 and 100, which certainly puts the 69 point rating of Greenwich Council into a little perspective. More importantly though is that SAP2001 was actually replaced in April by SAP2005 which has a 100 point scale instead.

We think the real achievement here is publicly announcing how good you are at energy efficiency by using the wrong measuring scale.