Air Conditioning Return Duct Size

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.

Air conditioning return duct size.

You have to consider the length of duct and the type of duct. Hvac engineers have developed manuals to cover all the ins and outs of how to size duct work. But a rule of thumb is just an initial guide not anything to bet your comfort on. Calculate the return duct size based on the air conditioner s size and the type of duct you are using.

4 tons x 144 square inches return air duct in square inches. Also you want to make sure that the return ducts are the same size as the supply ducts. Size of air conditioner example.