What is an Air Filter in an Air Conditioner and How Does it Work?

The air filter in an HVAC system is designed to trap particles and contaminants such as dust, mold, pet dander, and fungal spores. The mesh that gives the filter its name is made of a material that becomes denser as air passes through it, trapping these materials and allowing air to flow freely. If the air filter is not changed regularly, air will not be able to pass through as easily and more contaminants can get through the mesh, which can negatively affect indoor air quality.HVAC air filters do exactly what their name implies: they filter the air. This process usually occurs when spent air is returned to HVAC equipment for conditioning and distribution again.

As the air passes through the filter, the material removes particles and other contaminants from the air. A central air conditioning filter is usually made of spun fibreglass or pleated paper or cloth, enclosed in a rectangular cardboard frame.Fiberglass filters are the cheapest option and are typically one inch thick. They are commonly found in older systems. Newer models of central air conditioning use thicker pleated filters.

Generally, fiberglass filters should be changed every 30 days and pleated filters should be changed every 60 to 90 days. The effectiveness of an air filter is determined by how well it removes dust, pollen, and smoke from the air, as well as how freely air flows through the filter at any fan speed.An electronic air filter works by using an electric field to trap particles. The purpose of this type of filter is to keep the HVAC system clean, especially the evaporator coils, motor, and fan. The best filters trap indoor contaminants such as dust, pet dander, and pollen, helping to improve indoor air quality.

Standard MERV values range from 1 to 16; the higher the number, the better the filter will remove material from the air.In most cases, a standard filter cannot be replaced with a true HEPA filter because the ducts are not designed for it. The air filter is an important part of an air conditioning system because it prevents dirt from accumulating in the condensate and blocking it. A good air filter also keeps the central air conditioner (and boiler) working by protecting its mechanical components from dust and dirt. Air filters with higher MERV ratings have denser fibers that trap smaller particles more effectively.