SAP 2005 was introduced in April 2006 and undertaken to overhaul the previous SAP 2001 methodology. 

This edition of the standard assessment procedure (SAP) introduced the target CO₂ method of assessment, whereupon a SAP assessment must achieve a specified value, namely the TER or target emission rate to pass Part L. Pressure testing of dwellings was also introduced at this stage to confirm the air permeability of the structure at the post construction stage. Any failure to meet the minimum standard, or as a consequence create deviance away from the TER value, fails SAP. Expensive remedial measures are then required to meet what is required.

The code for sustainable homes (CfSH) also made use of this targeted system to identify its various ratings as a percentage reduction of the standard TER result. A dwelling designed to Code level 3 would have a target of 25% lower than the usual TER for example. In other words the DER would = 75% of the TER.

Another important part of SAP 2005 and SAP 2009 was been the introduction of Energy Performance Certificates (EPC). These were a later addition to SAP and were created to easily demonstrate the thermal efficiency of any building in an easily understandable manner.

These became mandatory on 1st August 2007, for all new dwellings (L1a)

This edition of SAP has now been superseded by the latest edition of SAP, SAP 2009