Heating with element (3)
I believe the answer is:
tin
'element' is the definition.
(tin is a kind of element)
'heating with' is the wordplay.
'with' indicates the answer is hidden within the clue.
'TIN' can be found hidden inside 'heating'.
(Other definitions for tin that I've seen before include "Earnings" , "roofing material" , "Atomic number 50" , "Silvery white metal" , "1 down, symbol Sn" .)