Temperature rating cut by half around large decorations (7)
I believe the answer is:
tassels
'decorations' is the definition.
(tassel is a kind of decoration)
'temperature rating cut by half around large' is the wordplay.
'temperature' becomes 't' (abbreviation).
'rating' becomes 'assessment' (I've seen this before).
'cut by half' suggests halving the letters.
'around' is an insertion indicator.
'large' becomes 'L' (eg in clothes sizes).
'assessment' halved is 'asses'.
'asses' going around 'l' is 'assels'.
't'+'assels'='TASSELS'
(Other definitions for tassels that I've seen before include "Ornamental bunches of cords" , "Adornments of bunches of cords" , "Decorations" , "Bunches of cords for decoration" , "Tufts of decorative hanging threads" .)