Cooler loft with central extraction is radical (7)
I believe the answer is:
fanatic
'is radical' is the definition.
(thesaurus)
'cooler loft with central extraction' is the wordplay.
'cooler' becomes 'fan' (something which cools).
'loft' becomes 'attic' (synonyms).
'with central extraction' means to remove the middle letters (the centre is extracted).
'attic' with its centre removed is 'atic'.
'fan'+'atic'='FANATIC'
(Other definitions for fanatic that I've seen before include "Devotee beyond reason" , "enthusiastic" , "Excessively devoted" , "Overzealous person" , "Zealot or extremist" .)