Synthetic air filters are typically composed of 100% non-woven polyester fibers, which are bonded together with a flame retardant to form a high density of elastic fibers. Pleatless air filters have a reduced filtration area or filter surface area, and are usually made of blown fiberglass or a less common synthetic material that can generate an electrostatic charge that attracts particles like a magnet. The American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE) developed the test method for determining the MERV rating. When considering the filtration capacity and efficiency of the air filter paper and the difficulty of processing the filter, the degree of whipping should not be too low or too high. Disposable filters in a bag-type filter system capture dust particles from the air that passes through them.
Adding a reasonable amount of synthetic fiber can improve both the filtration performance and physical strength of the filter paper. Foam filters with a higher PPI have a lower resistance to air flow than those with a lower PPI of the same thickness, and have a lower efficiency due to their larger open pores and less filter material for trapping particles. Aluminum air filters are made up of multiple alternating layers of aluminum mesh or mesh to maximize their filtering and particle retention capabilities. However, these air filters have a denser filter medium, which creates a higher initial static pressure and could result in lower air flow depending on the design of your HVAC. Most commercial air filters are designed to effectively remove solid particles such as dust, dirt, smoke, aerosols, odors, fumes, viruses, molds, bacteria, and ambient air particles and pollutants.
Unlike particulate air filters that are replaced due to static pressure, carbon filters are replaced once an odor or gas smoke breaks. The tensile and tear index of filter paper made from PET fibers decreased more smoothly than those made from PP fibers. The required replacement frequency of the activated carbon filter medium is unknown since it shows no signs of saturation. Dust holding capacity is the average weight of dust that an air filter can hold before reaching a specific pressure. The filter medium must be replaced or cleaned regularly to prevent clogging or blinding and restricting air flow. Carbon air filters are commonly used in air purifiers, range hoods along with aluminum screens, bathroom fans, and microwaves.
Fiberglass air filters provide better airflow in HVAC units and are suitable for capturing large particles.