Cold Air Return Duct Size

Capacities of air return intakes.

Cold air return duct size.

Your 14 x 20 return air inlet 280 sq. Houses often have two or more return collecting points each with a filter which join before re entering the heating unit. Use the following formulas. The following duct sizes are based on a fraction drop of 10 inches per 100 feet of lineal duct.

Calculate the return duct size based on the air conditioner s size and the type of duct you are using. The size of the filter at the air handler gives a clue about the anticipated size of the air return that equipment manufacturer expected to have. Cfm 10 x 4. A typical supply vent is 4 by 10 to 12 inches and a typical return vent is 16 by 20 inches or larger.

Larger volumes or higher static pressures should be dealt with on an individual job basis. In x in approximately capacity. Your filter size at the actual air handler is 20 x 20 400 sq in of air return. Click or tap here to get free bids in hours from local hvac companies to have new return air ducts installed in your home.

For instance a 2 5 ton system approximately 400 cfm per ton would require 2 14 flexible return ducts or 1 very short flexible 18 duct to move the 1000 cfm required by the 2 5 ton system. A return draws air into a return duct system with negative pressure compared to the space usually via a fixed grille but also often called a return vent or a return intake vent or for some of you old school folks from up north the cold air return. Air return intakes sizes and capacities pdf nominal size. An hvac return air can be in the floor but they work much better on walls up about 7 feet.

This equal friction method of duct sizing should be adequate for normal residential furnace heating and air conditioning applications. Size of air conditioner example.