Powerful, maybe too much so. I have an older section of my house where the insulation is not as good and only one duct feeding a large bedroom. I put one of these in. It was a 1940's register so I had to buy a new replacement and do some metal work on it. I have a Homeseer homeautomation system and used a ICON Relay - INSTEON Appliance Module to automatically activate the booster about a minute after the furnace kicked on. It comes on and really moves a lot of air. While you can hear it working, its not objectionable. Here's the but..... the placement of the duct put it near the bed. It blows so much air that the occupant felt cold from the breeze Two suggestions: 1 Don't plan to use it if the register is wall mounted / points direclty at where the occupants will stand, sit or sleep. 2 Buy the optional variable speed control, or buy an automation control that can dim a load. Also, if using automation, have it wait about a minute after the furnace on is detected to allow warm air to fill the duct.