Overheads involved in keeping warm (7)

I believe the answer is:

ponchos

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'overheads' is the definition.
The definition and answer can be both man-made objects as well as being plural nouns.
Perhaps you can see a link between them that I don't see?

I don't understand how the rest of the clue works.

Can you help me to learn more?

(Other definitions for ponchos that I've seen before include "South American capes" , "Mexican cloaks" .)

I've seen this clue in the Evening Standard.

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