Warmer -- presumably not on the peaks?
I believe the answer is:
storage heater
'presumably not on the peaks?' is the definition.
I can't tell whether this defines the answer.
'warmer' is the wordplay.
I cannot really understand how this works, but
'warmer' could be 'heater' ('heater' can be a synonym of 'warmer') and 'heater' is found within the answer.
The remaining letters 'storage' is a valid word which might be clued in a way I don't see.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Another definition for storage heater that I've seen is " Efficient domestic source of warmth".)