Static pressure is the resistance to airflow in ductwork. It is an important factor in evaluating the performance of an HVAC unit, and it can cause problems if it is too high or too low. Static pressure affects how efficiently an HVAC system runs, impacting how much energy is spent on energy bills. The right balance of static pressure is necessary for the system to function correctly.
HVAC static pressure refers to the resistance to airflow within the air ducts. For an HVAC system to function correctly, it needs to push air through the air ducts with greater intensity than the static pressure level within the pipes. If the system does not meet this condition, airflow will be affected.
Several signs indicate static pressure problems within an HVAC unit or ductwork. The following are the common indicators of static pressure problems in a home:
- A noisy HVAC unit
- Uneven temperatures throughout the home
- Higher energy bills
- Short cycling of the HVAC unit
- Reduced airflow from vents
The following are the common causes of static pressure problems in HVAC systems:
- Undersized air returns
- Dirty indoor coil
- Clogged or too restrictive air filter
- Ductwork that is too small
- Improperly sized heating and cooling equipment
To prevent static pressure problems, it is essential to choose an HVAC company that does a complete assessment of the entire system, including all units that comprise the HVAC system: furnace, air conditioner or heat pump, and ductwork. During HVAC preventative maintenance, a technician will measure static pressure in two locations within the unit. By doing so, the professional can zero in on where the air resistance is occurring. The total system static pressure when complete should not exceed 0.5 inches.
