Duct Work & Plenum

A typical tour of a house that our highly experienced inspectors would take prior to giving the homeowner an estimate or recommendation would include:

  • Duct Work – measure the sizes of supply ductwork and return ductwork to determine total cubic feet per minute (CFM) of air flow capacity.
    • Often, the original ducting system was sized improperly, or the home was ducted for heat only. As air conditioning systems require the movement of a large volume of air to properly cool and dehumidify the home, ducts that are too can not handle the volume needed.
Custom metal work is performed in-house prior to installation to ensure the quality of new duct installations
Custom metal work is performed in-house prior to installation to ensure the quality of new duct installations

 

  • In these cases, if we determine that CFM volume of the existing duct work is less than the recommended size of the replacement unit (for example, in a house that needs a 3,000 CFM (3 ton) cooling unit but with duct sizes that will only handle 2,000 CFM,) we will address the issue with the customer, and recommend how to correct the problem during installation to ensure the system operates properly.
  • While many homeowners are reluctant to have to pay for new duct work, we try to explain the importance to them, as ducting that is too small can cause damage to the a/c compressor and other components.
  • Plenum and return drop sizes – will they handle the air flow?

    • Plenums are enclosed spaces that are not for human occupancy, but are often used for heating, ventilating, and/or air-conditioning equipment placement and airflow, and for other equipment such as cables, piping, and luminaries.

    • ‘Plenum boxes’ or sections are portions of HVAC air handlers or terminal units.

Next: Space Limitations / Refrigerant Line Set