heating system vs heating

heating system and heating both are nouns.

Word	Noun	Adjective	Verb	Adverb
heating system	Yes	No	No	No
heating	Yes	No	No	No

As nouns, heating system and heating are synonyms defined as:

Other synonyms of heating system include heat, heating plant.

heating system (noun)	heating (noun)
utility to warm a building	utility to warm a building
	the process of becoming warmer; a rising temperature