Air filters are an essential part of any car, HVAC system, or other machinery. They are used to capture and remove dirt, dust, and other particles from the air, ensuring that the air is clean and safe to breathe. There are many different types of materials used to make air filters, each with its own advantages and disadvantages. The most common type of air filter media is paper.
This material is made from a very compacted wood pulp that is joined together to make a much stronger material. It is then folded into an accordion shape to give more surface area and is joined to a rectangle of foam. Paper filters are cheap and efficient, which is why they are so widely used. However, over time dirt will begin to clog in the folds of the material, which will restrict air flow.
Paper filters usually need to be replaced every one to two years or between 10,000 and 20,000 miles. Cotton-based air filters are another popular option. They feature layers of cotton gauze sandwiched between an aluminum mesh, which provides a less dense material for air to penetrate than paper. Cotton filters can last the life of the car, although they need to be cleaned and re-greased once they are sufficiently dirty.
Foam air filters are even less restrictive, using multiple layers of foam with different densities to stop contaminants, plus a wire mesh to help maintain the filter's shape. Metal filters are also available, made of stainless steel mesh layers. They do not need to be greased and have larger gaps between filter material than cotton or foam designs. However, they let more dirt through than other types of filters.
Fiberglass HVAC filters can remove most polluting particles from the air and are easy to maintain. Oil-dampened polyurethane foam elements are used in some aftermarket automotive air filters. This type of filter should be used with caution as it can cause oil to enter the mass flow sensor if it is over-lubricated. Oiled cotton gauze is used in a growing number of aftermarket automotive air filters that are marketed as high-performance items.
These filters require your HVAC system to work a little harder to draw air through the unit, which can cause your HVAC system to lose efficiency sooner than expected. Combustion air filter prevents abrasive particles from entering engine cylinders, leading to mechanical wear and oil contamination. Electrospinning technology as a way to produce nonwoven fibrous filters was developed in the 1950s to purify air in the atomic industry.