Mark Donovan of HomeAdditionPlus.com reviews AirFlow Technology's AirFlow Breeze Vent in this video.
The AirFlow Breeze vent is a great, energy efficient, low cost device for increasing the warmth, or coolness in a problem room within your home.
The AirFlow Breeze Home Heating/Cooling System (Almond) (Fits 4"W x 10"L opening)
and can be purchased on line at Amazon.com.