Crawl space or basement musty? That smell will drift up into the house.
Also high humidity will set off odors from old finishes like shellac; are you sure the odors aren't coming from old furniture, like a piano, dresser or rancid kitchen grease on the walls?
Our house built in 1914 will occasionally smell like an "old house" only if it has been closed up; the odor comes from the 1/2 cellar, 1/2 dirt crawl space.
The attic fan will get rid of it in a few minutes.

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