For those local space heaters that can be operated with different types and combinations of fuels: is the compliance with Ecodesign requirements needed only for the prefe

No. Ecodesign requirements need to be fulfilled with all fuels the product is marketed to be operated with.

^{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.}