In the winter, open the bottom registers and close the top. In summer, close the bottom and open the top registers. This draws cool air off the floor when it's cold and warm air off the ceiling when it's hot.
Then, is it better to close vents in unused rooms?
Despite that logic, it's actually a common misconception that closing vents in unused rooms saves energy. In fact, it can actually waste more energy than operating your system normally does. The added pressure from closing a vent can cause air leaks in your system, causing long-term and unnecessary energy waste.
How does the cold air return work on a furnace?
The answer may be your return air grills- also known as “cold air returns”. These are the vents that are usually on the wall and they do not have a control mechanism to open or shut their flow. Their purpose is to allow air to return to the furnace to be heated or cooled. It is an air inlet.
Which way do cold air return vents face?
The wide mouth opening should face the ceiling when mounted high, and facing the floor when mounted low. Return air grille mounted high near the ceiling: The top of each louvers should be closest to the grille face with the bottom of each louver slanted inward.