In the application of those factors to the calculation of energy performance, Member States shall ensure that the optimal energy performance of the building envelope is pursued.
Agus na tosca sin maidir le ríomh feidhmíochta fuinnimh á gcur i bhfeidhm, áiritheoidh na Ballstáit go saothrófar feidhmíocht fuinnimh an imchlúdaigh foirgneamh is fearr is féidir.