Suncourt 10-Inch NO 24V Motorized Damper, Transformer Included (ZO210)

This really works. Mine is in the attic, and I can't hear it at all from the 2nd floor bedroom just below it. The design uses a motor (not a solenoid) and has "lost motion" so the motor runs a few seconds before the driver bar actually engages the baffle. See the video for timing. You must leave power applied as long as you want it in the powered state... a spring drives it back to the starting position when you remove power.The motor gets very warm to the touch, but not dangerously hot. I measured the power draw and temperature but that was long before I wrote this review... maybe 10 W and 105 deg F? I'll update this review if I climb back up there and retest.I recommend using a power switch or plug with a built-in timer so you don't accidentally leave it in the actuated position all day and make your bedroom so hot the wife notices. Oh, and make sure you use plenty of foil hvac tape to avoid air leaks.Note: this design is either all-on or all-off... the design isn't amenable to driving the motor to a different position each time based on temperature measurements in the room.

24 volt transformer was missing with order. Also insulation strip was in wrong position so air was able to be supplied to room. Had to purchase transformer and new piece of insulation to get unit working properly.

Esto me funcionó excelente para dividir los ductos de un aire Central para dos áreas. Lo recomiendo