Questions? Feedback? powered by Olark live chat software

How does it Work?

HVAC System Air Flow

  1. Pick Your Filters
  2. Coose the Quality
  3. Tell Us How Often
  4. Start Service and Relax

Resistance is futile

All HVAC systems operate a fairly simple principle. Air is forced by a fan across heating or cooling coils, through a duct system and into building rooms. The same fan pulls air out of the building rooms through the return air ducts and back into the HVAC system for re-heating or re-cooling. Prior to re-entering the HVAC unit, the air is filtered to minimize dirt buildup inside the HVAC system and to ensure that clean air is blown into the building rooms.


Residential HVAC systems typically have a 1/4 or 1/3 horsepower blower, or fan, to move air through the system, air ducts and air filter. This small size limits the amount of resistance to air flow. Because air flow resistance is created by the ductwork, heating/cooling coils, grills and registers, the additional air resistance introduced by the air filter must be carefully considered.


Air flow resistance in an HVAC system is measured in inches of water column (w.c.). Residential units normally have about 0.5 inches of added pressure in the system, and the typical unit is allocated only about 0.03 inches w.c. for air filters. A high efficiency air filter introduces more air resistance that a low efficiency air filter. Additionally, air resistance increases as the filter becomes loaded with dirt and dust. This increase in resistance leads to a decrease in velocity of airflow in your unit.


For these reasons, selecting the appropriate air filter for your home HVAC system is critical to the efficient and cost effective operation of your HVAC system, clean air in your home, and the long-term return on the investment in your HVAC system. Click here for additional information to help you make the correct air filter selection.


Start your service today