More about today's air filters
Peter Kusterer, of Air Comfort For Homes and a member of Carteret-Craven Electric Cooperative, provided the following information to add to the basic summary we published about HVAC air filters. ["Clearing the Air," March 2013]
Originally ductwork was for distributing conditioned air, and filters were for keeping the coils and ductwork clean of hair and large dirt particles. As homeowners became more interested in indoor air quality, various types of media filters became available.
Design of the filter plays an important role in overall performance and use. Frequent changes and better performing filters can reduce maintenance costs, save energy and clear the air. However, not all filter designs are created equal.
It is true that filters with a higher Minimum Efficiency Reporting Value (MERV) block more dirt, but also reduce airflow and system efficiency. However, manufacturers have improved design beyond the traditional 1-inch pleated filter and offer high performance filters with low pressure drop. Aprilaire and Honeywell offer whole-home media air filters at or above MERV 8 without an adverse effect on the system's performance. The unique surface design of these filters can also offer MERV 11 protection and (in most cases) require only one change per year.
Homeowners should recognize that a filter is only effective when the system is running. Dust, pet dander, odors, smoke and other indoor pollutants occur year-round, and today's programmable thermostats and automation make it easier to clear the air when the system isn't running.
Running the fan only (if you know your ductwork is tight) can help clean the air. Aprilaire's "event-based cleaning" allows you to choose from a variety of pre-defined runtime settings, for example a three-hour period while vacuuming and dusting.
Your local HVAC professional or indoor air comfort specialist can help you choose the best combination of filtration and overall cost and system efficiency for their home.