Extended surface air filters, the most common type of air filters used in HVAC systems, increase the efficiency of airborne particulate removal without substantially reducing airflow. As a standard, flat panel filters become more efficient in function, but they also tend to restrict airflow in your ducts because they’re also thicker. Diminished airflow in an HVAC system causes a wide variety of problems, including icing of A/C coils, excessive furnace on/off cycling, increased component wear and tear and inconsistent comfort levels throughout the home. A common result is uncomfortable (too hot in the summer and too cold in the winter) sleeping areas on the second floor of a two-story home.
Extended surface air filters are usually composed of cotton or polyester fabric that’s pleated inside the filter frame to greatly increase the filter’s surface area without adding thickness that restricts airflow. This larger surface area increases the capacity of the filter to remove airborne particulates, often as much as 20 percent over standard filters. It also extends the service life of the filter. While inexpensive flat panel filters generally need to be changed monthly during peak heating and cooling seasons for optimal performance and efficiency, pleated extended surface air filters generally have a minimum service life of at least three months before recommended replacement.
The efficiency of HVAC filters is expressed by the MERV (minimum efficiency reporting value) system. MERV ratings range from 1 to 16. The higher the rating, the more effective the filter is at maintaining healthy indoor air quality in your home. Standard flat panel filters are ranked between MERV 1 and 4. Pleated filters are generally those with MERV ratings between 5 and 9. Some manufacturers have even deeper versions of this pleated filter which can be 4″ or more deep and that can improve the MERV rating to 13. These filters are effective at removing airborne particulates down to a size of 3.0 microns. This includes most household dust particles, as well as pollen, dust mites, carpet fibers and mold spores. NOTE: With any improved filter choice, it is always essential to make sure that the furnace or air handler is suited to the filter and that the added resistance that any better filter brings is within the capacity of the unit’s fan capacity to overcome this resistance.
P.K. Wadsworth Heating & Cooling helps Cleveland area homeowners maintain healthy indoor air quality year-round. Ask us about more benefits of upgrading to extended surface air filters in your HVAC system for increased performance and service life.