PLOT THINGS TO KNOW BEFORE YOU BUY

I know It will be great to have the air movement from downstairs to upstairs but is this a fire hazard?I are exploring my alternatives so as to add AC to my two-story, 1600 sq ft one hundred-yr-aged home. I've ducts but They're incredibly aged and would probably need to be redone, considering the fact that I don't have any returns on the next groun