What Is A MERV Rating?

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We do not see them with our naked eyes but indoor air pollutants are all around us. Every home has them in significant quantities. We can sometimes feel their presence as they trigger allergies, asthma, and other inconveniences. People who are sensitive to these particles should see to it that they change their HVAC air filters on a regular basis. The manufacturer’s recommended schedule should serve as the minimum standard. However, homeowners should check once a month to ensure that their filter is clean. The replacement filters must be compatible with the HVAC system as this impacts efficiency, indoor air quality, and more. Also, see the MERV rating to make sure. Read on to learn more about the MERV rating and its importance.

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What Is A MERV Rating?

Buying filters may seem easy but many get overwhelmed with the choices once they begin shopping. It is difficult to rely solely on product labels since every single one of them will boast about their excellence. With a little bit of research, you can begin to identify those that can’t back up their claims. Check the specifications and understand what each of these means. One of the terms you will encounter is “MERV” or the Minimum Efficiency Reporting Value. This represents the filter’s capacity to prevent pollutants from passing through. Higher numbers indicate better air filtration.

How MERV Ratings Work

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The rating system goes on a scale of 1 to 20. The first impulse is to get filters with the highest MERV you can find. However, this isn’t always the right course of action. Some systems will work better if you stick to the midrange filters while others demand extreme measures. The majority of homes will require filters that have a MERV rating of 5 to 13. On the other hand, hospitals, clean rooms, and nuclear power plants may need filters with MERV 16 to 20. It is generally not advisable to use filters that have MERV ratings lower than 5 because they are unable to improve indoor air quality by a significant amount.

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How is MERV Rating Determined?

The precise rating can only be found after filters go through a testing process. This is performed in a lab where particles of different sizes attempt to move across the obstacle. E1 is 0.3 to 1.0 microns while E2 is 1.0 to 3.0 microns. Lastly, there’s E3 which is 3.0 to 10 microns.

The human eye can only recognize objects that are 40 microns in width or bigger. Indeed, a single strand of human hair is barely visible at a diameter of 50 microns. Since these particles are much smaller, the test requires advanced lab equipment that is designed to detect them. They will be sprayed on one side of the filters while the detector is on the other side ready to measure how much was able to pass. The MERV rating is given from the results of the worst test score. A filter that is able to catch at least 95% of the particles is assigned as MERV 16.

MERV & Your Indoor Air Quality

The quality of indoor air will have a big influence on the health of the family. Those who frequently have allergy flare-ups should try using a filter that can capture more pollutants. Look for a product with a higher MERV rating than what you are currently using right now. By reducing the unwanted particulates, the allergy symptoms should subside while comfort increases. Individuals who previously had to deal with nonstop sneezing, runny nose, chronic fatigue, headaches, rashes, sore throat, and eye irritation can finally relax and breathe easily. Another benefit of this filter upgrade is the added protection it provides against dust and bacteria, as well as the damage that these can cause. The family won’t have to deal with illness as often as before. High MERV filters are great for people with compromised immunity.


Your Energy Use & MERV Ratings

The best way to catch smaller particles is to have even smaller filter holes. However, this comes at the cost of reducing airflow in the HVAC system. The equipment may compensate for this by working harder to move a larger air volume but this will require more energy. Residential HVAC systems are not usually built to handle the stress of using MERV 20 filters. These will only make utility bills shoot up and cause the equipment to break down eventually, although it is possible to modify the system to avoid this. Most homes should do fine if they choose filters in the range of MERV 8 to MERV 13. These can capture most contaminants in the air without being excessively restrictive with airflow. If you are not sure which one to pick, then talk to a trusted HVAC contractor for advice.

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How HVAC Air Filters Impact the HVAC System

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Forced-air HVAC systems have their own recommended specifications for air filters. It would be best to adhere as closely as possible to this range because deviations may cause unwanted consequences. Low-rated filters tend to be cheaper so budget-conscious individuals might be tempted to purchase them. However, this can lead to costly repairs in the future. It is not worth the immediate savings because they won’t be able to capture pollutants in a satisfactory manner. Dust will get into the ducts and build up inside the system, thus reducing efficiency and increasing energy costs. Going the other extreme of using a high-MERV filter is also bad as it decreases airflow, shortens service life, and hastens wear.

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Should I Buy Filters with High MERV Ratings?

High ratings are usually indicators of better products. It is natural for people to want things that are associated with superior performance when choosing HVAC components or other products. Just be aware that this is not the sole consideration when it comes to air filters. A top MERV rating may not necessarily produce improved outcomes in homes that are due to change their filters. Although these might capture more pollutants, they will be so restrictive that even air will have a hard time passing through. Bad airflow forces the system to use more energy. Even then, indoor comfort still won’t be as good. In the end, it’s all about compatibility between the filter and the equipment.

What MERV Rating Should I Aim For?

There is no single ideal MERV rating because all HVAC systems have their own distinct needs. Refer to the manufacturer’s instructions in the manual or consult your HVAC contractor for advice. If you can’t find the user guides, then just stay within the general recommended range which is MERV 8 to 13. Filters will this rating should have enough blocking power to capture most pollutants while still letting air pass through at a decent rate. Setting things up with compatibility in mind will allow you to get excellent results long-term. Households with only a handful of people and no pets can get away with a MERV 8 filter. If there are pets, then push this up to MERV 11. If there are lots of people including immuno-compromised individuals, then use a MERV 13 filter.



Given its massive impact on system performance and air quality, the MERV rating should be among the top factors to consider while shopping for air filters. This is the measure of the filter’s worst-case test results when subjected to impurities of various sizes. Extremely low ratings are your cue to ignore the products. These won’t be able to help you clean the air much. Extremely high ratings may not be ideal either if your system is not optimized to work with them. Instead, go for the mid-range filters for balance.

Get In Touch With Lawes Company For Quality HVAC Services

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Monmouth and Ocean County locals have always been able to rely on Lawes Company for expert heating, cooling, and air quality solutions. We are staffed by a talented and highly experienced team of HVAC technicians who offer tune-ups, repair services, heating and cooling equipment installation, HVAC replacements, and more. They are very knowledgeable, and they are sure to get the job done right.

At Lawes Company, we are committed to maintaining competitive pricing on all our heating and cooling services. With maintenance, you can limit your home energy bills and improve the efficiency of your HVAC system. Should you ever need to have your heating and cooling equipment repaired or replaced, we’ll help you find the right services and products for your needs and budget. Our specialists can also find effective strategies to improve the air quality of your home. All of our work is backed by our satisfaction guaranteed. Set up an appointment now by calling Lawes Company. Our in-home estimates are fast, convenient, and completely free.

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