SBEM (Simplified Building Energy Models) are required for all new commercial buildings and fall under Part L2 of the Building Regulations.
This was updated in 2022 to include the use of the Buildings Primary Energy Factor (BPER) as well as the previous Buildings Energy Factor (BER) both the BPER and BER must pass the BRUKL report for the building to now be signed off without concession from building control.

The BPER has caused issues in the passing the of SBEM, notably the calculation now assumes the notional building to which the model is calculated against carries PV. This meaning that unless your property is completely heated via a heat pump/split system then PV shall be required.

British EPC has undergone extensive tests and modeling in this regard to enable us to understand the methodology and obtain the required pass with some innovative HVAC system designs.