Warmer in home — timers are reset (9,6)

I believe the answer is:

immersion heater

I'm a little stuck... Click here to teach me more about this clue!

'warmer' is the definition.
Both the definition and answer are singular nouns.
Perhaps you can see a link between them that I can't see?

'in home timers are reset' is the wordplay.
'reset' is an anagram indicator.
'in'+'home'+'timers'+'are'='inhometimersare'
'inhometimersare' is an anagram of 'IMMERSION HEATER'.

Can you help me to learn more?

(Another definition for immersion heater that I've seen is " Electrical device".)

I've seen this clue in The Times.

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