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Measuring Furnace Air Filter Efficiency

MERV - Minimum Efficiency Reporting Value

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Measuring Furnace Air Filter Efficiency

Disposable Fiberglass Panel Filter: MERV 1 to 4

Everything gets measured and the efficiency of the air filter on your furnace is no exception. Furnace filter efficiency is measured by a MERV rating following the ASHRAE Standard 52.2 Test Procedure. MERV stands for Minimum Efficiency Reporting Value and is a measure of how effective the filter is in stopping dust and contaminants, including viruses, from passing through its media. Media is a name for the material from which the filter is made. Fiberglass, foam, specially treated paper and electrostatically enhanced synthetic fiber are common filter media.

The higher the MERV rating the more effective the filter is in removing contaminants. Ratings for home use typically range from 1 to 12. As you would suspect, the better performing filters are more expensive. The typical disposable fiberglass panel filter that comes to mind (and shown in this article) is the most common, cheapest and least effective filter available, with a typical MERV rating of between 1-4. The best filters for home use will have a MERV rating of around 11 or 12 and are made from deep pleated electrostatically charged synthetic gradient media, such as the AprilAire Space-Gard 2200 Furnace Air Filter.

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