Im trying to install a fan in a laundry room thats in a lower room of my tri level home. The only way I can figure to run the duct is through a chase made for heater ducts. I was thinking of running a rigid 3" pipe up to the attick close to the ridge vents. This run would be about 12-15 ft. the fan is a 70 cfm fan and trying to figure if its powerful enough or do I need to get one more pwerfull. I couldn't find any limitations on the instructions or manufacturer's website.