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The Air Filter and the Particles It Traps: Understanding MERV

Buying a new air filter for your air conditioner or furnace can easily become overwhelming. There are a number of different options available on the market and knowing to choose the best air filter for your household takes a basic understanding of MERV ratings.

Most HVAC air filters are labeled with a MERV rating. An air filter’s MERV (Minimum Efficiency Reporting Value) indicates the filter’s ability to capture airborne particles while air is flowing through your heating or cooling system. For residential purposes, MERV ratings range from 1 to 16, with the low-end filters only capturing the largest particles and the higher MERV ratings capturing increasingly smaller particulates. Here’s how it breaks down:

MERV 1-4.

This is a low-cost and disposable filter, commonly used for residential applications. Filters within this range are capable of only collecting the largest of particles such as dust mites, carpet fibers, dust and pollen. When it comes to improving indoor air quality, these are virtually useless.

MERV 5-7. 

Filters within this range do a better job of removing smaller particles. They might be used in both residential and industrial spaces and can remove airborne contaminants such as hairspray fumes, mold spores, and cement dust.

MERV 8-12. 

These are more efficient filters, and are common in homes where air quality is a concern. Their dense pleats are capable of removing extremely fine particles. However, because they operate so efficiently, they must be regularly checked and replaced.

MERV 13-16. 

These air filters are highly effective at removing most airborne particles including bacteria, but may not be the most appropriate air filter for your home as they tend to impede airflow. Some HVAC systems may require modifications, such as a more powerful blower motor, in order to use these high-end MERV filters. However, they are recommended for situations where pristine air quality is essential.

Whatever air filter you choose for your home, get in the habit of inspecting the filter monthly and changing or cleaning it when it looks dirty. It will go a long way in benefiting your overall home comfort.

{ 5 comments… add one }

  • Heather Graham November 23, 2013, 12:26 am

    Manitoba Hydro advised me to use one of the cheapest furnace filters, so their opinion is contrary to yours.

  • Andrew Morgan November 21, 2013, 7:54 pm

    It would be nice to know where one can get a Reliance installed replacement filter without incurring a charge for delivery and installation!! Our filter installed by Reliance in a new furnace is not a standard size it seems.

  • Rebecca November 21, 2013, 7:47 pm

    I have problem I have bad headache every morning where that from? And where to buy filter for my new furance…
    Please let me know as soon…
    Thanks you

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