When it comes to selecting an air filter, the answer may seem simple: Choose the one with the greatest particulate removal ability. However, in reality, there are more factors to consider than just particle efficiency, such as the effect of the filter on energy costs. Filter media, the component where filtration actually happens, can be very different despite looking similar to the naked eye. Lower-efficiency filter media typically has larger fibers and wider openings between fibers, allowing air to pass through easily. High-efficiency filter media, on the other hand, has smaller, finer fibers that can capture small particles via interception, diffusion, and straining. To filter small particles effectively, this type of media typically has a dense web of small fibers with smaller openings for air to pass through, making it more difficult for air to flow through.
These advances can extend the surface of the media, adding more surface area for air to come in contact with as it passes through the filter. This reduces energy consumption over the filter's lifetime, and in some cases, filters with synthetic media may have a relatively low initial resistance for their respective MERV ratings. However, these can lose efficiency as fibers become loaded with dust. It is also important to note that such filters tend to become dust-loaded more quickly, so they require frequent replacement and consume more energy to draw sufficient air through. The manufacturers we work with are always striving to design new and better medias, which can reduce resistance and energy consumption over the filter's lifetime.