Most homeowners understand the importance of filtering the airflow in their heating and cooling system. However, it can be confusing trying to decide which specific air filter is the best. Gaining a better understanding of the various options available and some of the attributes of different air filters can help you make the best choice.
Below is more information that will help you know how to find the right air filter that meets your needs:
Air Filter Rating
The primary way to evaluate an HVAC filter is by categorizing its ability to capture particles. Known as the Minimum Efficiency Reporting Value (MERV).
MERV rating measure is divided into a scale between 5 and 16; the lower the number, the larger the particle that can pass through a filter. For example, a MERV 5 rated filter may stop a dryer lint strand, but it cannot capture a microscopic fungal spore.
Another way to measure the capability of a given air filter is to evaluate its surface area.
Air filters with larger surface areas can capture more particles for a more extended period. Conversely, smaller surface area filters become full much more quickly and must be replaced more frequently.
HVAC filters can be evaluated based on airflow, as well. This characteristic is usually strongly related to the other two measures; for example, a porous filter media permits a high air volume to flow through due to its inability to capture a specific particle.
Types of Air Filter
Now that you better understand the air filter rating, you need to know the two types of air filters available. These include:
Strand fiber air filter
This class of air filters includes those with long, thin strands of some type of synthetic fiber or material.
Materials used include fiberglass and polyolefin fibers. This filter type has several advantages that make it a favorite of many homeowners. It is inexpensive and easily replaced, and it excels at filtering out large particles that can damage systems.
Strand fiber filters are not without cons. Most strand fiber filters have low MERV ratings, as they were unable to capture the smaller particles.
This can be a problem for persons who are sensitive to dander, dust, or pollen, for example. But, for many individuals who don’t have allergies or suffer from other air quality-related problems, the strand fiber filter should be the right choice.
Pleated air filter
Pleated air filters utilize a variety of fiber types, just as strand fiber filters do. However, pleated filters are designed to capture most of the smallest particles from the air, including those that negatively affect air quality.
These filters are manufactured with a dense weave of fibrous material set into the surface of the filter; since the weave is capable of capturing a lot of material, the MERV rating is higher as a consequence.
The fan-folded pattern of the fiber mat, which gives pleated air filters their name, also provides much more surface area than a strand fiber filter. This means they don’t need frequent replacement and can be used for months at a time.
The downside of pleated filters is that they require the fan to work harder to push the same volume of air as the strand fiber filters, thus lowering energy efficiency. In addition, they are more costly than strand fiber filters, though their longer service life should compensate for the higher upfront cost.
