HVAC Air Filter Ratings: Decoded

HVAC Air Filter Ratings: Decoded | PowersPeachtree City’s warm, humid climate presents no shortage of pollen, mold spores, and other air contaminants. The right HVAC air filter can do a lot to control those contaminants, and the more you know about filter ratings, the more easily you can find a filter that meets your needs.

Minimum Efficiency Reporting Value (MERV)

This number tells you how effectively an HVAC air filter traps particles of certain sizes. The higher a filter’s MERV number, the more efficient the filter. Filters with MERVs of 1–4 are considered low-efficiency filters. These keep debris out of your system, but don’t clean your air.

MERV 5–8 filters trap most of the pollen, mold spores, pet dander, and other small particles you could breathe in. These are sufficient for most households. If you have allergies or asthma, however, opt for a filter with a MERV of 9–12. As an added benefit, these higher-efficiency filters also last longer.

Higher-efficiency filters are often dense enough to impair airflow and potentially damage the fan motor in some HVAC systems. Before you buy one, have a technician check that your system can handle one.

High-Efficiency Particulate Arrestance (HEPA)

A true HEPA filter has a MERV between 17–19 and can trap 99.97 percent of airborne particles down to 0.3 micrometers in size. Filters labelled as HEPA-type or HEPA-like are less efficient. True HEPA filters remove not only very fine particles of dust and pollen, but also certain bacteria, smoke particles, car exhaust particles, and other contaminants most filters miss.

Because they’re so dense, however, HEPA filters usually can’t be added to home heating and cooling systems without some modifications. If you’d like to install one, a technician may be able to create a HEPA bypass system in your HVAC system. This limits the amount of air passing through the filter at any one time, so your system always receives sufficient airflow.

If you could use some guidance on choosing an HVAC air filter, contact us at Powers Heating & Air in the Peachtree City area.

Our goal is to help educate our customers in Peachtree City, Georgia and surrounding areas about energy and home comfort issues (specific to HVAC systems). For more information about air filters and other HVAC topics, download our free Home Comfort Guide or call us at 770-487-2040.

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