The Energy Performance Certificate (EPC) will be necessary in order to sell your property. Sellers are required to commission an EPC, however you don't require an EPC before marketing your property. This means that you, the Seller or a person acting on your behalf i.e. an estate agent; must instruct an accredited Energy Assessor to carry out an energy performance assessment.
An accredited Energy Assessor can be someone who is accredited (regulated) to provide energy assessments on buildings.
For further information please visit Directgov.