21.—(1) It is the duty of the relevant person in relation to an air-conditioning system to which this Part applies to ensure that the system is inspected by an energy assessor at regular intervals not exceeding five years.
(2) The first inspection of the system must take place before the relevant date.
(3) In this regulation “the relevant date”—
(a)where the system is first put into service on or after 1st January 2008, means the last day of the period of five years beginning with the date on which the system is first put into service; and
(b)where paragraph (a) does not apply—
(i)in the case of a system with an effective rated output of more than 250kW, means 4th January 2009; or
(ii)in the case of a system with an effective rated output of more than 12kW, means 4th January 2011.