BBS provide Part L2A compliance service in the following format:

1. ‘Design’ stage; whereby we will construct a virtual 3 dimensional model based
   on your building design, intended construction and proposed heating/cooling
   services. BBS will provide you with the necessary support and advice to ensure
   that your designs can achieve compliance.
2. ‘As-built’ stage; finalising the design stage calculations taking onboard
   changes and incorporating any applicable air pressure test results.
3. EPC (Energy Performance Certificate); this will provide you and any
   prospective purchasers or tenants with the predicted building energy efficiency.