Colour of bedroom with no central heating (5)
I believe the answer is:
amber
'colour' is the definition.
(amber is a kind of colour)
'bedroom with no central heating' is the wordplay.
'bedroom' becomes 'chamber' ('chamber' can be a synonym of 'bedroom').
'with no' is a deletion indicator.
'central heating' becomes 'ch'.
'chamber' with 'ch' taken away is 'AMBER'.
'of' acts as a link.
(Other definitions for amber that I've seen before include "Yellow fossil-resin" , "Yellowish colour" , "Follilised resin" , "Road warning" , "Yellowish fossilised resin" .)