Register Booster Fan Auto On/Off Pulls Warm/Cool Air from Inside Ducts Into Room

Register Booster Fan Fits 4" x 10" Register Holes, 10-Speed Smart Thermostat AC Vent Fan with Timer Setting & Automatic On/Off Once the Temp of Air inside Duct Reaches Your Preset Preferred Temp - Air Vents Fans with Remote Control Pulls and Circulates Air from Inside Ducts Into Rooms That Don't Receive Adequate Heating/Cooling Air Flow from HVAC/Furnace Due to Distance from HVAC Unit/Furnace or Competing with Nearby Register Openings - for Floor, Wall, or Window - Efficiently Moves the Warm/Cool Air from One Side of the Booster Fan Into the Room the Fan Faces.

Clever energy efficienct design: In winter mode the device is programmed to detect when hot air starts to flow through the ducts once the furnace is turned on. As soon as your pre-set temperature is reached inside the ducts, the fan turns on to help pull in and spread that heat throughout the room.

The same for summer mode—when your A/C kicks on, the fans turn on and pulls the cool air from the ducts into the room to cool it.