Air Return Duct Design

Ductwork design mistake 5.

Air return duct design.

Ducts that are not well designed result in discomfort high energy costs bad air quality and increased noise levels. To maintain balanced air pressure and air movement your duct system needs return vents for air in the room to be pulled back into the hvac system. The return air vent openings need to be on the opposite side of the room so the conditioned air is pulled across the room. Duct design 4 calculating friction rate.

In the winter this means you re losing. The science of sag flex duct and air flow. Placement and design of return air ducts and vents is a crucial factor in how efficiently and effectively conditioned air will circulate in your home. This pulls the air across your body.

Square ells return or supply are a bad idea. Central air return ducts. If supply air doesn t have a way to return to return ducts it will leak out of the house through cracks and openings in the home s outer envelope. Not providing enough returns is a common ductwork design flaw that leads to comfort complaints.

This video is chapter 5 in the e learning course on design of air distribution system offered by octave simulation services pvt. This means that when certain doors are closed the air supply can be cut off and create an unbalanced pressure system. Again an experienced contractor can rectify this problem by simply installing a return duct in each room that has its own supply duct. If the supply ducts are in the floor then the return air should be located up high.

If the supply ducts are high or in the ceiling then the return air ducts or grills should be low on a wall. Don t kill your air flow with this flex duct disease. Each one in a system can add as much as 80 to the tel. The third example shows a return air base beneath the air handler furnace.

The 2 primary causes of reduced air flow in ducts. Many homes have been designed to have a centrally located air return. This is the best configuration and mandatory if the unit has a 5 ton blower. It s important that roughly the same amount of air moves through supply ducts as return ducts in order to maintain neutral air pressure in rooms.

Choosing the right sized duct is critical to maintain proper air flow in the system. Rounded throats on ells drastically improve airflow especially a rounded inside throat. The secret to moving air efficiently through your duct system my article on david hill s 2015.