Flex Duct Size Calculator

Duct system sizes and airflow quick chart created date.

Flex duct size calculator. Flexible duct friction loss calculator. Flexible duct work must be stretched tightly for maximum air flow. Input the required cfm in the box below that. Rectangular duct is rounded up to the nearest 1 4 inch.

If ashrae 2013 is selected flexible roughness is 0 003 ft when straight and fully stretched tight at 0 compression adjusted at other compressions otherwise the. Calculations are for 60 f dry air at sea level from 5 to 3000 cfm approximately standard air which is 0 075lb da ft. The flex duct size may be different than the hard duct that runs to that room. Friction rate velocity friction rate.

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. Calculate the size of your ducts vents by multiplying the length by the width. Friction loss inches water duct airflow cfm duct length feet 90 bends quantity 45 bends quantity 180 bends. Include fittings in the duct tel enter either.

Select the duct type on the pull down menu. Always stagger take off ducts by 12 to maintain pressure. 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. Metal ductboard flex size by.

The duct vent size will depend on the size of the furnace and the size of your home so you know how many vents you need in each room. 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 step one identify the volume of air that will be passing through the duct step two select the duct size from the table that can carry that volume of. Never locate ducts at the end of the trunk line run. Last take off run to be located 12 18 from end.

Use the online duct calculator see references and calculate the needed flex duct size. In order to maintain velocity reduce duct size. While this may be true in most cases for a metal supply air duct it is not for a metal return nor a 6 flexible duct on supply or return. In wg duct tel.

Use insulated duct or duct board in unheated spaces. Click calculate and you will see the size of flex duct you need for that room.