Any promotional or sales document which contains information about technical parameters or visual elements, be it also press notifications or written purchase offers, must include the energy efficiency class and available classes.
Disclaimer: Please note that the European Commission cannot provide a legally binding interpretation of the EU legislation, as this is the sole competence of the European Court of Justice. Any remarks from the European Commission services are without prejudice to the position the Commission might take should related cases arise in a procedure before the Court of Justice.