Air Filter Selection and Replacement for Optimizing Indoor Air Quality and HVAC System Efficiency

Just as the type of fabric used in a face mask can influence what people breathe from their surrounding environment and exhale into the air, building air filters can also have a significant impact on the indoor air quality (IAQ) of a home or building. Air filters play an important job in the HVAC system, trapping particulates, which could include allergens, asthma triggers, respiratory irritants, infectious pathogens and other contaminants, as the air circulates.
 
Unfortunately, since air filters are typically out of sight, many people forget to change them on a routine basis. If not regularly replaced, they can become overloaded with dust and particulate matter which can make the HVAC system run less efficiently, increasing energy costs and perhaps decreasing the life of the system. A dirty filter may also negatively impact IAQ if it is no longer properly removing airborne matter. In a high humidity environment, a dirty filter could even support the growth of mold.
 
While following the manufacturer’s recommendation for how frequently to change a filter is an excellent place to begin, there are other factors that can come into play. For example, how frequently is the HVAC system used; how large is the home or building; do family members or building occupants suffer from allergies, asthma, COPD or other respiratory conditions; are there pets indoors; and is the property in an area prone to outside air pollution, high pollen counts or dusty conditions?
 
“There is no universally applicable frequency for changing HVAC filters. Temporal and site-specific dynamics dictate the ideal timing of filter replacements. Factors to consider include, but are not limited to, season, hours of daily operation, occupant density, indoor activities, filter type, filtration goals (e.g. basic HVAC protection or infection control) and the like.” said Derrick A. Denis, Vice President of Indoor Environmental Quality (IEQ) for Clark Seif Clark. “Filters are classified with minimum efficiency reporting values (MERV) based on how efficiently they remove particles in various sizes ranges (e.g. 0.3-1.0µm, 1.0-3.0µm, and 3.0-10.0µm). Unique structures demand goal-oriented filtration, such as residences, clean rooms, airborne infection isolation rooms (AIIRs), etc. The higher the MERV rating the more effective the filtration of airborne particles, but the more restrictive the filter media. Dense filter media that exceeds the design specifications leads to excessive air resistance, reduced air flow and adverse pressure drops, which can lead to problems like frozen coils, extreme duct leakage, premature system wear and more. Don’t use the highest MERV rated filter you can afford, but instead, use the MERV rated filter your HVAC system is designed and rated to handle. Change the filters on the manufacturer’s recommended schedule or more frequently as needed.”
 
Dedicated to creating healthy and efficient indoor environments in homes, businesses and institutions are the professionals at Clark Seif Clark. Their building science, air quality, industrial hygiene and infection control experts offer building assessments and testing services to identify indoor pollutants, support infection control efforts, and evaluate ventilation and filtration issues. CSC also recently sponsored an educational video about air filters in residential settings that can be seen at: https://youtu.be/p6N6sEWKtvA
 
To learn more about this or other indoor air quality, building science, infection control, environmental, health and safety services, please visit www.csceng.com, email csc@csceng.com or call (800) 807-1118. 
 
About Clark Seif Clark
CSC was established in 1989 to help clients in both public and private sectors address indoor air quality, occupational, environmental, and health and safety (EH&S) issues. CSC is a leading provider of these services with multiple offices along the western seaboard and southwest. The company believes in science-based protocols and has a strong background in engineering, making them the preferred environmental consultants to industrial clients, healthcare facilities, architects, schools, builders, contractors, developers and real estate professionals.
 

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Paul Cochrane

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