references to the person responsible for the use of any heat generator are references to the owner or, if a person other than the owner is in possession of the generator under any agreement, the person in possesssion under that agreement;

references to efficiency, in relation to any heat generator, are references to its efficiency of operation, and references to standards of efficiency shall be construed accordingly;

references to a heat generator subject to on-site testing are references to a heat generator of any description to which an on-site testing order applies ;

references to an on-site testing order shall be construed in accordance with section 10(1) of this Act; and

references to a testing authority shall be construed in accordance with section 9(10) of this Act.