«temperatura utile dell’acqua» (Tm), la temperatura dell’acqua espressa in gradi Celsius, alla quale l’acqua calda inizia a contribuire all’energia di riferimento, come indicato nell’allegato III, tabella 7; ###>‘useful water temperature’ (Tm) means the water temperature, expressed in degrees Celsius, at which hot water starts contributing to the reference energy, as specified in Annex III, Table 7;