The HVAC system in any home or building must be balanced between supply and return. A balanced system refers to one that draws in and puts out equal amounts of air and creates uniform pressure throughout the building envelope. If your HVAC system is not balanced the heating and cooling of your home will not be evenly distributed, creating areas that are too hot or too cold.
One way to achieve balance is to put a return register in each space that also has a supply; the negative pressure created by the return is neutralized by the positive pressure of the supply in each area, equally distributing hot or cold air through the building envelope.
However, in some situations it is not possible to have return ducts in each room. An easy fix for this problem that will still ensure even pressure and therefore even cooling and heating of your home is to install jumper ducts.
Jumper ducts are short runs of duct that connect two separate spaces but are not connected to the rest of the HVAC system. Once installed, they look just like any other register in the home. Even though they are not directly connected to the return plenum, a jumper duct acts as a quasi return by allowing air to flow from a room with no return to a space with one.
Luis Imery, through his business the Imery Group, is a full service construction, home energy performance, green certification and real estate group specializing in infusing sustainability in every facet of the real estate cycle. Its construction division has become pioneers in the Athens, GA area in green building of speculative, custom and design-built construction. Just in 2011 they have over 110 units slated for green certification under the EarthCraft program.