Thanks for the info. The reason for choosing a 12v fan was to eleminate having to make a 110v power run from the breaker box. I was thinking of picking up 12v power from either of the smoke detectors in the living room and using wire molding to conceal the wire run. I have not taken a measurement of the clearance between the opposing slides, I hope there is enough room. The fan I am considering is a ceiling hugger and the lowest point from the ceiling is 5 1/2".