6-Inch 110VAC 250 CFM In-Line Duct Fan

This unit is decent and exceptionally quiet, BUT THE SPECS ARE MISLEADING. It says right on the box for these that they're 250 CFM (Cubic Feet per Minute). But that figure is for the maximum flow of air if you're boosting air that is already moving. If you're replacing a unit that has 240-250 CFM "Free Air" (i.e. this is the only thing moving the air within the duct), then the CFM rating is only 160. So when I tried to place a 240 CFM (Free Air) fan, this thing only had 2/3 of the power and probably moved about half as much air in reality.

Unfortunately, I had to look this up online to find that out. Now I need to get a bigger unit.

I put this in the duct leading to the master bath. It's at the far North-West corner of the house. I had almost no air coming out of the duct before, now it's blasting out quite well.
Because of the airflow, it's louder than before. But all I hear is air rushing over the grille. I really can't hear any vibration from the fan.
The instructions say to install the fan 6 feet from the grille. In my case, those last 6 feet are insulated flexible duct. This plastic and fiberglas duct just isn't going to conduct any motor vibration.
For a switch, I used Senasys 100°F Fan-Style Snap-Disc Switch: Closes on temperature rise. With this switch, the fan won't turn on when the air conditioning is operating.
This model does require wiring. So you do need some basic electrical skill to install it.
I've posted some...Read more

I had purchased this item as a fan for a hydroponic grow tent and was originally dismayed when it arrived and did not have a power cord, just three wires: green, black, and white. I took a spare PC power cord, cut off the end that plugs into the PC and stripped the internal wires off. The color on each of the 3 internal wires matches the wires on the fan. I then used 3 all-weather winged wire nuts that I purchased for a few dollars at my local home improvement store to join the wires. I connected the power cord into a DuctStat to control the fan. I am using a low-heat LED array based grow light so I did not need high througput airflow and my grow tent has a 6" opening at the top that this fan fit into perfectly. I used a 6" duct clamp to secure it place. This has been an inexpensive solution, my second choice product was over three times the price.