convector vs warmer

convector

noun
  • A space heater that transfers heat by convection; a radiator 

warmer

noun
  • Something that warms, such as a heater or a soup. 

  • An introductory activity, for example in a lesson, to stimulate interest in a topic. 

  • A piece of clothing for warmth, such as a bodywarmer or leg warmer. 

How often have the words convector and warmer occurred in a corpus of books? (source: Google Ngram Viewer )