WhisperCeiling incorporates an integrated dual 4" or 6" duct adapter to give you flexibility in duct layout and design. For short runs, you can go with a smaller duct size, but long runs are OK, too - just move up to 6" duct. The double hanger-bar system (expandable up to 24") is ideal for positioning the fan exactly where you want it. Panasonic fans are UL listed for tub/shower enclosure (just install them on a GFCI-protected circuit). With these great features, your installation options open up.