conference center vs conference house

conference center and conference house both are nouns.

Word	Noun	Adjective	Verb	Adverb
conference center	Yes	No	No	No
conference house	Yes	No	No	No

As nouns, conference center and conference house are synonyms defined as:

conference center and conference house: a center where conferences can be conducted

conference center (noun)	conference house (noun)
a center where conferences can be conducted	a center where conferences can be conducted