How to Make a Return Air Duct Work

The HVAC unit conditions air in the home, removing humidity and particulates and turning warm air into the chilled air we love on hot summer days. The proper placement of return air ductwork for your HVAC unit determines your comfort in the home. Comfortable cooling in summer and heating in winter result from the right location of the return air duct and its ability to send air back to the coil. Placing the return air duct in the right spot prolongs the life of the unit.

Duct calculator
Sheet metal material and tools

Instructions

- 1
  Size return air ducts properly. The ideal cubic feet per minute (CFM) determines the size of the return air duct needed. As a rule of thumb, every 450 square feet of a home will require a ton of heating and cooling. Calculators, such as the Lima Register air duct calculator, help with this determination.
- 2
  Locate return air ducts in outer walls. Cooling of the outer walls encourages faster and more efficient indoor cooling and allows the return air duct to work with less effort.
- 3
  Place return air ducts near the thermostat, or relocate the thermostat closer to the ducts. Return air ducts should be as short and straight as possible to encourage uninterrupted airflow back to the coil.
- 4
  Calculate the right duct size for the interior coil inside the unit. Undersized returns create a whistling noise. Oversize the return duct to eliminate noise and allow air to travel freely.
- 5
  Undercut doors that remain closed, such as those of the spare room or a teenager's refuge. This assists air movement and allows an easier return to the unit.

Disconnecting a Chimney Flue Pipe

My Furnace Does Not Keep the House at a Set Temperature Consistently

Heating & Cooling Repair