Flex Duct Size Calculator

Select the duct type on the pull down menu.

Flex duct size calculator.

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. Click calculate and you will see the size of flex duct you need for that 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. Flexible duct friction loss calculator.

Rectangular duct is rounded up to the nearest 1 4 inch. Duct system sizes and airflow quick chart created date. For example if the vents are 5 by 10 inches the total cmf for the vents is 50 cmf per vent. Never locate ducts at the end of the trunk line run.

Calculations are for 60 f dry air at sea level from 5 to 3000 cfm approximately standard air which is 0 075lb da ft. In order to maintain velocity reduce duct size. Friction rate velocity friction rate. 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.

Include fittings in the duct tel enter either. Enter friction loss per 100 of duct inches of water duct airflow cfm duct length and the number of bends. Always stagger take off ducts by 12 to maintain pressure. Friction loss inches water duct airflow cfm duct length feet 90 bends quantity 45 bends quantity 180 bends.

Flexible duct work must be stretched tightly for maximum air flow. Input the required cfm in the box below that. Use the online duct calculator see references and calculate the needed flex duct size. Read duct diameter inches and duct velocity fpm.

Last take off run to be located 12 18 from end. Use insulated duct or duct board in unheated spaces. 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. 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. The flex duct size may be different than the hard duct that runs to that room.