HVAC Air Filter Ratings: Use More Than MERV To Select One

Installing high-quality air filters minimizes the amount of dust, pollen, mold spores and other pollutants floating around in the air of your Delaware home. Without a basic understanding of HVAC air filter ratings, though, it’s hard to know what makes one filter better than another. To make comparing filters easier, get familiar with the helpful ratings developed by The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE).

MERV, or minimum efficiency reporting value – One of the most common HVAC air filter ratings, this number indicates the efficiency of media-type air filters, such as fiberglass and pleated paper. The higher the MERV, the more efficient the filter. A filter with a MERV of 7 to 13 is nearly as efficient as a HEPA filter.

Dust-spot efficiency – This rating indicates a filter’s ability to remove dust particles — usually larger particles — from the air in a laboratory setting. Look for HVAC filters with a dust-spot rating between 35 and 80 percent.

Pressure drop – Also known as filter resistance, this describes the effect airflow through the filter has on the HVAC equipment’s energy efficiency. Generally, a low-pressure drop allows for greater energy efficiency. Filters with a greater surface area, such as pleated filters and bag filters, usually have a lower pressure drop than those with less surface area.

Dust-holding capacity – This describes the amount of dust a filter can hold until it reaches a certain pressure drop. A higher dust-holding capacity means the filter will last longer. When you compare filters’ dust-holding capacities, make sure you compare them at the same final pressure drop.

Initial and sustained efficiency – The initial efficiency rating indicates a filter’s ability to trap airborne particles when the filter is brand new. This doesn’t always indicate overall efficiency, though. The sustained efficiency rating is the average efficiency the filter can sustain over its lifetime.

If you’d like more expert guidance on understanding HVAC air filter ratings and choosing the filtration system that’s right for your home, contact the experts at Sobieski Services.

Our goal is to help educate our customers in Wilmington, Delaware and surrounding areas about energy and home comfort issues (specific to HVAC & plumbing systems).

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