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07_04_13Air filtration is a vital component of indoor air quality. As the air circulates through your HVAC system, it passes through the filter, which captures and holds particulates and contaminants such as dust, mold, pollen, and even micro-organisms and bacteria.

When choosing an air filter to use in your heating or cooling system, you should pay particular attention to the filter’s MERV level. MERV stands for Minimum Efficiency Reporting Value, and is an industry-wide rating of filter efficiency. MERV ratings indicate how effective a filter is at trapping airborne particles as small as 0.3 microns in size.

MERV ratings start at 1 and range as high as 16 for residential filters. Higher MERV numbers indicate better air filtration efficiency and the filter’s ability to capture smaller particles.

  • MERV 1-4: Air filters in this MERV range are usually low cost, but they are only minimally effective. They are best at collecting particles of 10 microns or larger.
  • MERV 2-8: Medium-quality filters such as these are usually made of a pleated filter material that presents more surfaces where particles can be trapped. They are best against contaminants of 3 microns or larger.
  • MERV 9-12: These are high-quality filters that are very good for general use in air filtration. They can handle particles of 1 micron or larger.
  • MERV 13-16: These filters offer the highest efficiency air filtration for residential systems. They work well at removing smaller particulates of 0.3 to 1 micron. However, when the MERV numbers get this high, the filter may impede airflow, which will reduce system efficiency and performance. High MERV filters also may require system modifications in order to work properly. Consult with your HVAC technician on what air filter will work the best in your particular system.

Crawford Services, Inc. brings years of experience and customer care to the cooling and heating services it offers throughout the Dallas area. Contact us today for more information on the importance of air filtration and how to choose an air filter with the right MERV rating to meet your indoor air quality needs.

Our goal is to help educate our customers in North Texas about energy and home comfort issues (specific to HVAC systems).

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