Does your heating, ventilation and cooling (HVAC) system suffer from excessively high or low static pressure? You may want to check the air filter. Air filters can affect static pressure. They can contribute to high or low static pressure while subsequently causing other problems with your HVAC system. By understanding the connection between air filters and static pressure, however, you can better maintain your HVAC system.
Static Pressure Explained
Static pressure is a measurement of airflow resistance in the ductwork. To supply your home’s living spaces with conditioned air, your HVAC system must overcome this airflow resistance. More specifically, the blower must be powerful enough to effectively push the conditioned air into and through the ductwork. Static pressure is a measurement of this resistance.
High static pressure indicates a high level of airflow resistance. The blower will have to work harder to push the conditioned air into and through the ductwork. Low static pressure indicates a low level of airflow resistance, in which case the blower will easily move the conditioned air through the ductwork.
Dirt and Debris
Air filters that are clogged with dirt and debris will contribute to higher static pressure. All air filters will catch dirt and debris. After all, that’s how they clean the air in homes. As air flows through the filter, it will remove particulate matter, including dust, dirt and mold.
Neglecting to replace your HVAC system’s air filter, though, may lead to high static pressure. In most residential HVAC systems, the air filter should be replaced at least once every three months. By the end of three months, it will be clogged to the point where air struggles to flow through it. The clogged filter will restrict the flow of air, in which case your HVAC system’s static pressure will increase.
The minimum efficiency rating value (MERV) of an air filter will affect static pressure. Developed by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), MERV represents an air filter’s ability to remove small particulate matter. It ranges from 1 to 16. Some air filters have a low MERV rating, and others have a high MERV rating.
Air filters with a high MERV rating will remove more particular matter, but it comes at the cost of restricted airflow. Air won’t be able to flow through them as easily as air filters with a low MERV rating. Therefore, using an air filter with a high MERV rating can cause high static pressure.