Air Filters

Basic Air Filter – What You Should Buy

The most common type of air filtration through your heating and air conditioning system is a disposable filter. Did you know all air filters are not the same? Some filter very little while others filter so much they reduce the air-flow in the system. This causes the system to run longer and with air-flow conditions it was not designed for. For most households, the ideal filter is somewhere between the least and most effective.

Furnace manufacturers prefer the traditional spun fiberglass filters (MERV 2) because they filter out enough of the larger particles to protect the furnace while providing maximum airflow. Maintaining the manufacturer’s specified airflow is critical to achieving energy efficiency and ensuring maximum lifespan of the furnace.

It stands to reason that the ability to filter smaller particles would come with decreased air flow. A shift to higher MERV filters creates airflow reduction. This can cause problems with inadequate cooling and heating plus greater energy use. Inadequate air flow stresses furnace components and causes it to run longer.

The Minimum Efficiency Reporting Value (MERV) scale is from 1 to 16. Most residential filters range from 4 to 12. A MERV 7-8 pleated filter provides a good balance between cost and filtration efficiency. A MERV 8 filter traps 80 to 95% of particles 5 microns and larger, providing good filtration for most households.

If you have smokers in the house, live in an area with high air-pollution, or have family members with allergies or low-immunity issues, a MERV 11 or higher filter makes sense for you. High-efficiency filters capture 99% of airborne particles as small as 0.3 microns (bacteria and viruses, fumes and pollen). For you, the reduction in air flow and increased operating costs are justified.

NOTE: The higher the MERV, the quicker the filter needs to be replaced. A higher MERV rating is made possible by reducing the filter media’s pore size. The smaller the pore, the faster the filter clogs.

The best way to determine if a filter needs to be replaced is by installing a new one while the blower is running and making note of the difference in the sound of the air movement. You can check the difference in sound (caused by reduction of air flow) of the new filter against the filter you think might need replaced.

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Call Al’s for more information about our Indoor Air Quality solutions and how we can help you keep your home’s air clean and fresh. 972-225-5257 or contact us online.
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