Heating device (8)
I believe the answer is:
radiator
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">heating device</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for radiator that I've seen before include "Heater -- or cooler!" , "Apparatus for heating" , "Its content is wet!" , "Domestic heat source" , "Room heater" .)