When a building is sold, rented, or built, a valid Energy Performance Certificate (EPC) is required by law.
As soon as you begin marketing your property for sale or rent, you must make the EPC available. This would inform people about the property's energy efficiency, as well as any potential fuel savings.
The EPC, which contains information about a property's energy use and typical energy costs, must be created by an approved/accredited Domestic Energy Assessor.
If you follow any of the energy efficiency recommendations in your EPC, you may want to have a new EPC completed to reflect these changes. A fine may be imposed if an EPC is not valid.