WhisperGreen Select is a ground-breaking IAQ that is revolutionizing the ventilation fan industry with a newborn set of features that enable customization and easier installation. To the builder and professed installer, Panasonic to be the innovation leader with utmost performance ventilation solutions that are built to sunset. WhisperGreen Select 's unequaled design and brilliant energy efficiency are through engineering expertise, provided by a company who sets the stock for quality and value. WhisperGreen Select the identical new DC motor that comes with our WhisperGreen line of products. With constitutional SmartFlow technology, WhisperGreen Select is to perform as rated. When the fan faces adynamic pressure, its speed is automatically to ensure optimum CFM output. This feature peace of mind, as the installer does n't have to worry about compromising the fan 's performance. ASHRAE, ENERGY STAR, LEED for Homes, and HVI have the industry stock for performance measurement at .25 '' w.g.. The WhisperGreen Select fans not sole compelling CFM output at .25 '' w.g., but our sones have also been certified at .25 '' w.g. so they are unagitated under pressure and after installation. duple 4 '' or 6 '' canal adaptor -LRB- up to 110 CFM models -RRB-. constitutional metal flange blocking for penetrations through drywall as an air barrier, and assists with the decrease in leakage in the building envelope during blower door testing.