What is Air Balancing?

What is Air Balancing?Air balancing is the critical process of ensuring that your heating and cooling system conveys the proper volume of air to each room through the supply ducts while removing an equal amount through the return ducts. An HVAC system is a closed loop that continuously recirculates a designed amount of air measured in CFM (cubic feet per minute.) When an imbalance exists, certain rooms are often always too hot or too cold. The problem can be divided into two categories:

Rooms are over-pressurized: more supply air volume than return volume. Heating and cooling is pushed out of the house through tiny cracks and gaps in the structure. Energy efficiency declines and interior comfort suffers.

Rooms are de-pressurized: more return air volume drawn out than supply volume delivered. Negative pressure sucks hot or cold outdoor air into the room as well as potentially contaminated air from unconditioned zones like the attic or crawl space. Comfort and efficiency decline and indoor air quality is jeopardized.

Causes of airflow imbalances include:

  • Clogged filter.
  • Duct leakage.
  • Improperly adjusted air dampers.
  • Defective blower.
  • Obstructed air path to a central return.

Air balancing requires a trained technician with expertise in specialized equipment like air balancing hoods to measure air velocity and volume at each vent, manometers to measure system pressure in the ducts and hygrometers to measure temperature and humidity. With this data the technician can identify imbalances on a room-by-room basis. Correcting air balance may be as simple as replacing a clogged air filter or removing obstructions like draperies from vent openings. In most cases, however, it means adjusting dampers inside branch ducts to regulate airflow in and out of rooms until a stable state of neutral air pressure is restored. Because changes to air volume in one room affect airflow system-wide, the procedure will require re-measurement of air volume and fine-tuning of dampers to achieve the best result. After all rooms are balanced, the dampers are secured in a fixed position.

For more information about air balancing your Detroit or Grosse Point home for efficiency and comfort, contact Aladdin Heating & Cooling.

Our goal is to help educate our customers in Warren, Michigan about energy and home comfort issues (specific to HVAC systems).  For more information about air balancing and other HVAC topics, download our free Home Comfort Resource guide.

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