Duct Sizing Hvac Cfm Chart

Flex duct has a higher pressure drop and as such may require the size shown on this guide be increased by 1 round size for up to 800 cfm and 2 round sizes.

Duct sizing hvac cfm chart.

If a room is 250 square feet the result will be a duct size of 8 inch round. Duct system sizes and airflow quick chart created date. Flex duct 05 on most metal duct calculator round metal pipe 06 on most metal duct calculators field duct sizing chart rectangular sheet metal duct 07 on most metal duct calculators duct size. This equal friction method of duct sizing should be adequate for normal residential furnace heating and air conditioning applications.

The chart should not be used to design complete duct systems. Larger volumes or higher static pressures should be dealt with on an individual job basis. To insure proper distribution of air volume dampers must be used for all branch runs. Air volume equivalent round air volume cfm 4 6 8 10 12 duct inches cfm 50 6 x 4 550 75 6 x 4 675 100 8 x 4 6 x.

Calculate the duct size by using a duct calculator. The chart is based on metal duct. For the same 2 5 ton system with a filter grille the grille size would need to be what size asked rick we usually use a 20 x 20 for 2 5 ton said the tech 20 x 20 x 2 800 800 cfm well that s big enough for a 2 ton but a 20 x 25 may be a better choice.