tumble dryer vs washer-dryer

tumble dryer

noun
  • An electrical device that dries clothes in a rotating drum which tumbles the clothes in a flow of hot air. 

washer-dryer

noun
  • A machine that combines a washing machine and clothes dryer. 

How often have the words tumble dryer and washer-dryer occurred in a corpus of books? (source: Google Ngram Viewer )