Hvac Return Duct Sizing

Particle diameter opening size.

Hvac return duct sizing.

Energy savers julie boleware julie boleware has been writing since 1997. Most technicians are skeptical about these numbers especially on the return air side of the system. Duct sizing how to size ductwork. How many square inches do i need to get the right airflow for 3 tons.

While a duct sizing calculator built for a specific type of ductwork is the best possible method for sizing ducts the attached chart can be used in most single story homes with a centrally located unit and reasonable length duct runs. 8 7 rules of duct design acca manual d residential duct systems 9 0. An insufficient return system or one too large will reduce the efficiency of the heating and increase energy bills. Duct system sizes and airflow quick chart created date.

Link 1 and link 2. I have a three ton downflow furnace a c. These ductwork tips will help balance your air conditioning and heating system. 10 3 fire and smoke dampers.

10 1 duct fittings and transitions. Return duct systems. How do i calculate if the return ducts are too small too. These charts hold a lot of information.

Both returns are above the ceiling with lengths of 12 and 8 feet two ninety. Design cfm 4 cfm 6 cfm 8 cfm 10 cfm 12 60 6x4 60 4x6 90 4x8 120 4x10 150 4x12 90 8x4 110 6x6 160 6x8 215 6x10 270 6x12 120 10x4 160 8x6 230 8x8 310 8x10 400 8x12 150 12x4 215 10x6 310 10x8 430 10x10 550 10x12 180 14x4 270 12x6 400 12x8 550 12x10 680 12x12 210 16x4 320 14x6 490 14x8 670 14x10 800 14x12 240 18x4 375 16x6 580 16x8 800 16x10 950 16x12 270 20x4 430 18x6 670 18x8 930 18x10 1100. I already learned from reading other posts my return grills are too small. She has been published on the internet public library and various websites.

To size the ducts you re going to need a duct sizing chart. 9 1 distributed return. Therefore your return air duct and grill size will be 24 by 24 inches tip. Particle diameter strainers and filters mesh size vs.

10 2 volume control dampers. 9 3 pressure balancing. If the furnace is putting out 1 000 cubic feet per minute of air flow the return system must collect 1 000 cubic feet and take it back to the unit. Hvac ductwork sizing is critical for proper heating and cooling in every room.

If you don t have one you can find them in the following links. A furnace return system must collect all the air being put out by that system. 9 2 central return. I have two return ducts hard metal round one 14 inch and one 12 inch.

Have to get the air back to the furnace. Always place return ducts as far away from the supply air vents as possible. You can obtain these from ductwork manufacturers or from industry bodies such as cibse and ashrae. Air intakes and outlets ventilation systems air intakes and outlets rules of thumbs.

Duct fittings and terminal units.