It is important that you consider how efficient the filter is at removing particles when choosing a 20x20x1 air filter. The Minimum Efficiency Reporting Value (MERV) rating gives you an indication of how efficient an air filter is. These ratings can range from one to twenty. Higher ratings are better at removing smaller particles at a higher rate. The MERV rating is important, because particles less than 10 microns in size can pass right into the lungs.

20x20x1 air filter


The MERV of air filters is the filtering efficiency of a particular filter. It can range from one to sixteen. The MERV is determined by the size of the particle, so the higher the number the filter, the better. Twelve different sizes of particles were created in a laboratory. The smallest particles are approximately 40 um and the largest about 50 um. These particles were then divided into three groups, ranging in size from 0.3 to 1.0 um to 3.0 bis 10.0 um.

Microparticle performance rating

There are two methods for determining the effectiveness of air filters: the MERV rating and the Microparticle Performance Rating (MPR). The American Society of Heating, Refrigerating, and Air Conditioning Engineers developed the MERV rating, which is the most popular. The MERV rating refers to the amount of pollutants or particles that can pass through the filter. 3M has a newer system called MPR. It ranks manufacturers according to their ability to trap airborne particles between 0.3 and 1 microns.

Electrostatic filter

Electrostatic filters clean the air with the power of static electricity. Static electricity is a natural phenomenon that occurs when air flows through fibers subject to static charges. These charged particles will attract and hold onto each other until the filter is washed and re-used. After each use, an electrostatic filter will last for years if it is cleaned regularly. The device can also produce ozone to reduce pollution.

Pleated filter

Pleated air filters have many benefits. They are more affordable than non-pleated filters, despite the higher price. Your preference will depend on how sensitive you are to pollutants and whether you are allergic to certain elements. The main purpose of your filter installation will determine what type of filter you need.

Oil-wetted polyurethane foam filter

A Polyurethane Foam filter is a filtration medium that has been impregnated in oil. The oil composition can include up to 94% of petroleum oil and 5% of methylene chloride. The foam is then exposed to high-pressure air jets in order to weaken its cell walls and membranes. After the foam has been wetted, the jets cause it to expand and rupture, releasing any remaining oil and particles.

Media filter

Media filters are designed to trap air pollutants and odors before they enter your home or office. They are typically located in the return line of your HVAC system. These air cleaners are rated according to the Minimum Efficiency reporting Value (MERV). The MERV ratings, which range from 1-16, indicate the protection they offer against various pollutants. A media filter can make it easier to breathe if you have asthma or allergies.