Bests & Worsts Reviews from Amazon

The stated specs for this little fan unit are 240 scf/m and 37 watts. At that volume of air movement through a 6" duct the velocity should be 14 mph at the discharge of the fan housing. I measured the air speed (with a wind speed gauge I use for optimizing whirligig blades) and it was 15.0 mph. That is 259 scf/m so the fan's raw output without the drag, resistance and turbulence caused in flexible expansion ducting is producing air movement slightly higher than advertised. I ran the fan on my Watt Meter and it was using 40 watts which was close to the 37 watts advertised and is a match for the slightly higher volume of air. I have mounted this fan in the garage ceiling over the boiler and hot water heater area with 15 feet of 6" ducting running to the floor. During the winter I have it running to pull hot air off the ceiling and recycle it back to floor level to give me a more even temperature. For 32 States whose electricity is less than 13 cents/KW (2014 data), this fan would cost less than $3.75/mo of continuous running based on 13 cents a kilowatt. For my purposes it definitely has reduced my natural gas heating bill in the winter by cutting down the number of times the garage thermostat calls for heat. And its more comfortable working in the garage in the winter now too. I plugged this fan into a Wireless Remote controlled outlet unit so I can shut it off whenever I want to save energy when its not needed. For the $25 price tag I've made it all back in energy cost savings during the first winter. Fans of this size are not very quiet since they need high RPMs to move the rated volume of air. In a living space area it wouldn't be a very good choice BUT you could use a sheet of that silver bubble wrap insulation wrapped around the outside of the housing which should dampen the noise a bit more.