Household device for re-heating kippers (8,7)
I believe the answer is:
electric blanket
If this is the answer, I'm afraid I cannot explain it.
Can you help me to learn more?
(Other definitions for electric blanket that I've seen before include "Bed warmer" , "cover at night" , "this might warm you up" , "Bed heater" , "Provider of extra bed heat" .)