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What is a Furnace Filter and How Does it Work?

Interested in learning about furnace filter and its operation? Keep reading!
Priyanka Kosta Sonkushre May 13, 2019
The U.S. Environmental Protection Agency reports that indoor air is around five times more polluted than outdoor air. This happens because indoor pollutants keep on adding to air and the same air keeps on circulating without being replaced for a long period of time.
Facts suggest that a person breathes around 18,185 liters of air everyday. This air contains numerous airborne particles and dust, most of which are 3 microns or less in size, and are tiny enough to enter the air passage and reach lungs.
These particles can be harmful enough to cause serious complications in people residing in the house. It is therefore important to ensure that the air circulating indoors is clean and healthy. Maintaining clean indoor air has become easy with the advent of furnace filters.

What is a Furnace Filter?

A furnace filter was initially designed to protect the furnace and the fans of the indoor heating system. It is a detachable filter made up of standard fiberglass, and is placed between the air inlet and the furnace fan, motor, and heating panel.
Its prime use is to protect these internal parts from dust particles which can reduce the efficiency of the furnace. Airborne particles tend to accumulate on the furnace motor or fans thus, increasing the workload and decreasing the efficiency.
The need of clean air for respiration has now come in the forefront. With this concern gaining importance, furnace filters are now being used to improve the quality of indoor air. Filters available today are redesigned to protect the internal parts of the furnace along with enhancing the quality of the air.
The standard fiberglass filters are now replaced with highly efficient filters capable of filtering very fine particles from air. People suffering from asthma and other allergies can make use of high-efficiency filters to create a pollutant-free environment and reduce the incidence of their medical condition.

How does a Furnace Filter Work?

In the absence of a filter, the air that is sucked in through the inlet of the furnace system comes in contact with the motor and other parts. As the air drawn is contaminated with dust and other airborne particles, it is likely that they accumulate within the furnace and damage the motor, fan, and heating coil.
Excessive choking will force the motor to work harder which will result in overheating and complete shut down of the motor. As replacing a motor can be an expensive affair, furnace filters are used to tackle this problem.
Fixing furnace filters after the air inlet ensures removal of dust particles and helps in passing filtered air through the system. Dust and particulate matter get entrapped in the filter, letting clean air go further.
Clean air is ensured by entrapment of pollen grains, dust mites, allergens, and other pollutants. Such filters work for around three months with complete efficiency after which, they should be replaced with a new filter.
Furnace filter replacement must be done after specific intervals to maintain quality air in the home surrounding and improve life of the furnace. Filters made up of cotton, foam, or paper operate by mechanical entrapment of particles, whereas electrostatic filters use ions to attract and entrap airborne particles in the filter.
Furnace filters range from cheap to expensive. The cost of a filter is directly proportional to its efficiency. Greater the efficiency of a filter in providing clean, particulate-free air, higher is its cost. The quality of a furnace filter is judged by Minimum Efficiency Reporting Value (MERV). Higher the MERV, better is the quality of a filter.
If you are interested in maintaining a long life of your furnace and enjoy the benefits of clean air, look beyond standard fiberglass filters. The cost of such a filter will be on the higher side, but it would be worth it. People sensitive to particulate matter can go with high-efficiency filters to breathe in a clean environment and stay healthy!