Hot air from this duke, essentially lost title (8)
I believe the answer is:
demister
'hot air from this' is the definition.
(a demister gives off hot air)
'duke essentially lost title' is the wordplay.
'essentially lost' suggests removing the centre (the heart or essence of the word is removed).
'title' becomes 'mister'.
'duke' with its middle removed is 'de'.
'de'+'mister'='DEMISTER'
(Other definitions for demister that I've seen before include "control of car" , "Remover of condensation" , "one good at clearing" , "Device for removing condensation from a windscreen" , "One gives a clear view" .)