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Air filters are the best defense your Lake Forest, Illinois, home has against contaminants entering your air supply. These filters follow a classification called MERV. This rating scale can tell you a lot about the filter you’re considering, so understanding how it works is very important. Here are three things you need to know about the MERV rating scale.


MERV stands for maximum efficiency reporting value. It is a rating scale from 1 to 20, with 1 being the lowest and 20 being the highest. Filters rated from 1 to 4 are the cheapest filters and are often made of cardboard and lower-grade materials. Next are the 5 to 13 category filters. These filters are the most commonly purchased and are high enough quality enough for most families. The 7 to 13 category filters are typically used by families with serious allergy concerns and can be as effective as HEPA filters. An actual HEPA filter has the highest score: a perfect 20. HEPA filters are used in commercial applications such as hospitals and not typically used in homes.


For most families, a filter rated anywhere from 5 to 13 is enough. These are commonly available in hardware stores and aren’t too expensive. Since it is important that you change your filters regularly, you should keep in mind that a rating less than a 5 is acceptable, but you will be sacrificing extra filtration for a lower price. Filters that are higher than 7 are a little more expensive, but do a better job removing pollen and other unwanted contaminants.


Your filter can affect the efficiency of your HVAC system. Filters that are thinner let air through easily, while higher rated filters can make it more difficult for the HVAC to pull in air from outside, thus increasing the amount of energy expended in the climate control process. Some HVAC units have a specific MERV range that works best with that particular system, so be sure to check out your user manual and talk to a certified technician to ensure your selected filter won’t impair the ability of your HVAC.

The experts at Ireland Heating & Air can help with all your filter and HVAC issues. Give us a call at 847-388-0108 to set up a consultation today!

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