Part L of the Building Regulations covers the conservation of fuel and power in buildings.
In order to avoid more onerous requirements, your project will need to begin on site before 6th April 2014, or be subject to a building notice, full plans application or initial notice submitted before this date and work starting within one year.
For new dwellings, the main changes to Part L1A are:
A reduction in energy usage; a 6% saving on carbon dioxide emissions relative to the current Part L 2010.
An improvement in energy efficiency; a new requirement to achieve a fabric energy efficiency target. gcp have experience of designing to this target since its introduction in the Code for Sustainable Homes in November 2010.