RHAN 2Diwygio’r Rheoliadau Adeiladu
Mewnosod rheoliad 25D o’r Rheoliadau AdeiladuI17
Ar ôl rheoliad 25C (adeiladau newydd: gofynion perfformiad ynni gofynnol) mewnosoder—
Energy efficiency rating25D
Energy efficiency ratings must be approved by the Welsh Ministers, applying the methodology of calculation and expression of the energy performance of buildings approved pursuant to regulation 24 for new buildings.