Air filtration systems may be doing a lot more for your building than you think.
Air filters work by trapping and collecting particulates, biological materials, and gasses as air moves through a building’s HVAC system. Initially, air filtration systems were used in commercial buildings to protect HVAC units, reducing the need for facility cleaning.
In recent years, attention has been given to indoor air quality issues as people have studied Sick Building Syndrome (SBS) and its relationship to reduced productivity and attendance. Facility managers have the responsibility of providing higher quality indoor air to their building’s occupants before they suffer the effects of low-quality indoor air.
Air filter minimum efficiency reporting value (MERV) ratings measure the effectiveness of the filter as it relates to preventing dust and other contaminants from passing through the filter and into the air stream. A filter with a higher MERV rating will trap small particulates more effectively than a filter with a lower MERV rating.
MERV ratings range from low efficiency (MERV 8) to medium efficiency (MERV 13) to high efficiency (MERV 15).
Higher rating does not always mean better. Depending on the manufacturer’s recommendations for your building’s HVAC system it could potentially impair its performance. Air filters with higher MERV ratings can create resistance to air flow and when they are used in HVAC systems that cannot handle the resistance then it will actually decrease the indoor air quality, as well as decrease the system’s efficiency and limit its lifespan.
The operating cost is specific to the building, no matter what efficiency is of the filter. Even after considering the recommended filter from the HVAC system’s manufacturer, the building’s location, traffic, and specific air quality concerns will all factor into the operating costs.
Costs can be saved in the long-run for multi-filter HVAC systems. The multi-filter system will extend the life of more costly final filters when paired with one or more pre-filters. The pre-filters catch larger particles before the air reaches the final filters downstream, which removes smaller particles. Allowing pre-filters to do the bulk of the work will lead to more time between final filter changes.
High-efficiency-particulate air (HEPA) filters have the highest MERV ratings, between 17 and 20. These filters are used in hospitals to create sterile rooms, removing 99.97 percent of dust, mold, bacteria, pollen, and other particles from the air.
Typically, office buildings and many other commercial buildings will find it difficult to retrofit an existing unit to accommodate a HEPA filter. This is where we run into the issue of the filter causing strain to HVAC systems and decreasing the air quality. Most sources indicate the typical MERV rating that standard HVAC systems will support is between 13 and 16.
Why is air quality getting so much more attention now?
“I’ve been writing consistently since early February about how healthy buildings should be the first line of defense against the novel coronavirus,” Joseph Gardner Allen, who directs the Healthy Buildings program at the Harvard T.H. Chan School of Public Health, said to CNN.
The concerns about minimizing infection has provided indoor air quality with more attention than before, but it isn’t a new issue. Sick Building Syndrome (SBS), a common health concern caused by the buildings people are occupying, has been understood for years. SBS symptoms can often be similar to allergy-like symptoms and can include headaches, runny nose, throat irritation, or breathing difficulties.
The effects of poor indoor air quality leads to reduced productivity and it impacts decision making. Advanced ventilation systems are becoming more popular in both residential and commercial HVAC systems because they enable user to monitor air quality, allow higher airflow from the outside, and can feature new air purification technologies.
Looking to the future
The majority of modern office spaces use filters rated MERV 13 or higher as building owners have seen the potential to market their buildings as a high-quality indoor environment. As more facility managers recognize the importance of higher quality indoor air, there is hope that it will become the norm rather than a luxury that can be used to justify higher lease prices.
Schools and health care facilities especially need to consider air filter options because children and individuals with underlying health risks are more susceptible to respiratory infections. There is additionally the aerosol transmission of infection that could prove to be especially harmful to people staying in healthcare facilities or children attending school.
The emphasis on higher quality indoor air during the COVID-19 pandemic allows us to take the time to consider what improvements can be made in commercial building environments. We all spend so much time indoors working in offices, going to school, getting medical treatment, or even doing leisurely activities like reading a book or playing the piano; why not do everything possible to make the space we spend the majority of our time a healthy one?
Many point to the cost of filters and the expense of retrofitting buildings and say it may not be worth it. That’s not always the case, Allen said to CNN. “It’s a total misnomer that healthy building strategies and higher ventilation rates and filtration are expensive strategies,” Allen said. “When people know and understand how it’s transmitted, then they’re empowered to make better decisions.
Because of the concern of infection spreading through the air, facilities managers can benefit from finding new resources available to them to improve on indoor air quality. Improving indoor air quality may help your occupants feel better and become more productive, thus providing you with great results and a healthier building.