Years ago, air conditioning filters were just used to keep the evaporator coil and blower clean. Today, they are an important, and sometimes overlooked, part of your air conditioning system because they are used to filter out particulates in the air stream.

The significance of this is that air filters are now used to clean the air in the home, not just the air conditioning system.

There are many types of air conditioning filters on the market today:

• Standard 1” throw away

• Pleated air filter

• Electrostatic filters

• HEPA air filters

• Electronic air filters

An air filter’s effectiveness is measured in an MERV (Minimum Efficiency Reporting Value) rating. This scale is designed to represent the worst case performance of a filter when dealing with particles in the range of 0.3 to 10 microns (a micron is equal to one thousandth of a millimeter). MERV ranges from 1 to 16. The higher the MERV rating, the better the air filter.

Standard 1”:

A standard 1” air conditioner filter is made of spun fiberglass and has cardboard frames. It is only capable of removing 10% of airborne pollutants. Standard 1” air conditioner filters only remove larger particles and does not filter harmful allergens and contaminants very well. You have to change these filters every month.



Pleated filters are manufactured by folding filter material back and forth and have a larger surface area than standard filters. They are capable of removing 35% to 40% of harmful particles in the air. Pleated air conditioner filters are slightly more expensive than basic air conditioner filters, and you need to replace them once every three months.



An electrostatic air conditioner filter uses filter media that has an electric charge that attracts contaminants. They can have a built-in electrostatic charge, or create a charge from the air moving through the system. Electrostatic air conditioner filters can remove around 90% of particles. You only need to replace them once every three months.



Another type of air conditioner filter is HEPA or High-Efficiency Particulate Arresting filter. They are able to trap 99.97% of contaminants including fibers, dust, smoke, and pet dander. They can effectively trap particles 1/300th the width of a human hair!



Electronic air cleaners function much like electrostatic filters, but they are more effective. They use a fan to trap up to 95% of particles in an electrostatic precipitator. These devices are usually recommended if you have allergies.