The higher the number, the more restricted the airflow. Diagonal support members on both sides ensuring filter pack rigidity. Fibrous Filter Media,Philip J. "@type": "Question", Take it out and run the system for a couple minutes. In the end, well finally see why HEPA filters are called HEPA (and reveal which filter is even better than the HEPA filter). "@type": "Answer", Conclusions Drawn from the MERV 13 Pressure Drop Chart $3,834 will be saved annually per AHU in reduced fan energy by using 5-Star air filters. According to the standard's application guidelines, particles in this size range include pollen, dust mites, mold spores, hair spray, powdered milk, and of course, snuff. 1994-2021, W.W. Grainger, Inc. All Rights Reserved. Pre filters are rated MERV 2. Changing your air filters regularly will prevent filters from being loaded and overly restrictive. Filters down to 10.0 micron particle size, Filters down to 3.010.0 micron particle size, Filters down to 1.03.0 micron particle size, Filters down to 0.31.0 micron particle size, Filters down to less than 0.30 micron particle size. Efficiency is measured by the percentage of particles captured. A: Although ASHRAE does not recommend a specific MERV filter rating for preventing COVID-19 transmission, the organization suggests that upgrading systems in non-healthcare facilities to MERV-13 or the highest achievable level can be a worthwhile step in emergency response plans. Note that when the MERV 13 is added, it is more restrictive than either. However, an important factor is that MERV ratings are not standard and the quality of a filter will vary from one brand to the next, meaning that pressure drop will vary between different filters that are rated the same. The majority of residential HVAC systems use a 1 thick filter, but filters are available at 2, 4 and 5 thick. A lock (LockA locked padlock) or https:// means youve safely connected to the .gov website. While it is true that the more resistance to the flow of air results in a greater drop in air pressure on the other side of the filter, it isnt always true that higher MERV means higher pressure drop. Hi Nash, ASHRAE 52.2 is the source of all MERV effectiveness data. "text": "When you air filter is installed, it is a barrier between your HVAC and your ducts/vents. Bryan. "name": "How is filter pressure drop measured? A MERV 8 filter can remove particles down to 3 microns in size at an efficiency of 70 percent or greater (1 micron is about 0.04 thousandths of an inch). Do you know what could happen if you didnt get the right ones? The final pressure drop/final resistance is measured when the filter has reached its total dust holding capacity and is ready to be replaced. How often should I change my filter if I have a high MERV rating? You can check the whole EPAs list of air pollutants here. Static pressure is the measurement of the exertion of air flow your HVAC system is moving throughout the system and ductwork. This also means that as the MERV rating goes up, the more particles and contaminants the filter can capture. Do I Really Need to be Concerned with the MERV/Pressure Drop Issue? In particular, using an air cleaner with a MERV rating that is too high can damage the compressor, heat exchanger, and air conditioner coil. Typically, the higher the MERV rating, the higher the pressure drop and the more restrictive the air flow is. Filters with higher MERVratings trap small particles more effectively than filters with lower MERVratings. This Standard is what led to the creation of the minimum efficiency reporting value, or MERV. Doing so could cause strain on your HVAC unit and could cause costly maintenance and repairs. AFI Replacements (Air Bear, Honeywell, Trane), Poly Anti-Microbial Tackified 1 Inch Media 10oz, Poly Dry / Dry Tackified 2 Inch Media 15oz, Twist-Lock Cylindrical Cartridges for Pneuma Pulse, Flange-Top Cylindrical Cartridge for Farr Tenkay, Conical Cartridge for Donaldson GDX & GDS, Cylindrical Cartridge for Donaldson GDX & GDS, HEPA Crank-Lock Housing 2 Inch Pre-Filter, HEPA Crank-Lock Housing 4 Inch Pre-Filter, 2020 Air Filters, Inc. All rights reserved. Manufacturers are in continual competition to try to provide the best of both worlds in this area. The minimum efficiency reporting value, is a number from 1 to 16 that is relative to an air filter's efficiency based upon particle size. This MERV rating chart has the MERV ratings, 1-16 on the left hand column and then there are five other columns showing the average efficiency in microns, average arrestance and the final resistance as measured in inches of water. The Back pressure from this filter is 0.22 WG. This method tests Air-Cleaning Devices for dust removal efficiency. This 4 inch filter has over 60 square feet of synthetic dirt grabbing fibers. MERV stands for Minimum Efficiency Reporting Value. All filters will increase in pressure drop in use. 3.0-10.0 greater than or equal to 80%, 0.30-1.0 greater than or equal to 35% There are many benefits to having a higher MERV rating, including: If you have a high MERV rating, you should change your filter every 3 months. 3.0-10.0 greater than or equal to 70%, 1.0-3.0 greater than or equal to 50% Generally, increasing filter efficiency leads to increased pressure drop which can lead to reduced air flow through the HVAC system, more . Their cost is often moderate and are within many budgets. The filters initial pressure drop (initial resistance) will vary by the filter type, MERV rating, and size. The Velocity (speed) of the air flow is tested at 1 of 7 different speeds. What MERV filter is recommended for preventing the transmission of airborne illnesses such as COVID-19? . "name": "What initial pressure drop vs. final pressure drop? The higher the MERV of a filter, the smaller and the more particles it will remove from the air that passes through it. Grainger Editorial Staff. 3M Filtrete MERV 5 Review Conclusion. "text": "The pressure drop of a filter is a measure of its resistance to airflow through it. in the Inch-Pound system of measurement. These particles are 1-3 microns. This type of air filter can theoretically remove at least 99.97% of dust, pollen, mold, bacteria, and any airborne particles with a size of 0.3microns (m). Heres one example: We compared three filters of a popular brand and the same size (20x25x1) with MERV 5, MERV 11 and MERV 13 ratings. That's all. JavaScript seems to be disabled in your browser. Contaminant Size Intervals. The amount of E1, E2 and E3 dust particles that are captured and missed is calculated. Depending on what size of particles the air filters can trap or let through, they are classified in a chart known as the MERV rating. } It also shows air filter efficiency levels. },{ Using the MERV rating chart to understand the filters and their applications. As air moves through a buildings HVAC system, air filters trap and collect large and small particles such as dust, allergens and microorganisms. LakeAir provides discounts to Veterans, First Responders, and the Elderly. Most current household HVAC units/handlers can handle a MERV 6-13 pleated filter with ease. It should be noted that pressure drop through a high-MERV filter varies depending on the velocity of the air flow. This MERV rating chart has the MERV ratings, 1-16 on the left hand column and then there are five other columns showing the average efficiency in microns, average arrestance and the final resistance as measured in inches of water. These filters are installed in two air handling units (AHUs) in the Delaware Biotechnology Institute. When used in a multi-filter system, the pre-filters trap the dirt and large particles before the air reaches the final filters downstream, which then remove the smaller particles. There is still a common misconception that having a high MERV rated filter will be too restrictive and strain your unit. The higher the pressure drop the more restrictive the filter is to air flow. Depending on the design [] The E3 arrestance describes how well an air filter removes larger particles such as dirt, lint, hair, and dust. We are here to make sure you select the right solution for your needs. ", A MERV rating chart shows a numerical value. Particle filtration can be "modestly effective" against allergy and asthma symptoms. They used a 20 x 20 filter. Pressure drop directly corresponds to a filters air flow rate." Particles that are larger or smaller are trapped with even higher efficiency. } However, most HVAC systems built in the last 20 years should have no issue using a MERV 6 - MERV 13 rated air filter. As an Amazon Associate we earn from qualifying purchases. 52.1-1992 ASHRAE Test Procedure ATMOSPHERIC DUST SPOT EFFICIENCY 1. Q: Can HVAC operations strategies help prevent the spread of COVID-19? "@type": "Answer", An air filters minimum efficiency reporting value (MERV) rating measures how effectively the filter stops dust and other contaminants from passing through the filter and into the air stream. The higher the MERV, the smaller the particles removed, and the more of them removed. This one of the main reasons why it is so important to check, change, and clean your air filter every month to help ensure your air filters pressure drop does not get too high and cause strain on your air conditioner/handler. If we were looking to buy a new filter today for our HVAC (heating, ventilation, and air conditioning) system, we'd aim for a medium-efficiency filter with a MERV rating in the 8 . Your efficiency will drop measured by higher energy costs: Systems working too hard burn more fuel or use more electricity to get the job done. The test is made of six cycles. It is an acronym for "high efficiency particulate air [filter]" (as officially defined by the U.S. Dept. Frequent filter changeouts will help minimize risks from pressure drop. Performance MERV 8 Air Filter MERV 11 Air Fir Filter Particle Size 3.0 - 10.0 microns 1.0 - 3.0 microns % Particles Captured 90% 95% Lasting Time 3 months 2 - 3 months Level of Usese Basic - Standard The filter is assigned a value based on the test. 2. While it is true that the more the air filter traps the more effective it is at capturing more particles; it will eventually become too loaded, at which point, the airflow could be zero and extremely restrictive. Here's what you're not being told. This results in lower air pressure on the side of the filter from which the air exits. The more tightly woven or thick a filters media is, the more particles and contaminates the filter can trap. Air filters can be used as final filters or pre-filters. If you're looking at air filters rated for MPR compared to air filters rated by the MERV filter rating system, you can reference this chart below: MPR 600 is equal to MERV Rating 8; MPR 1000 is equal to MERV Rating 8; MPR 1200+ is equal to MERV Rating 11; MPR 1500 is . This one of the main reasons why it is so important to check, change, and clean your air filter every month to help ensure your air filters pressure drop does not get too high and cause strain on your air conditioner/handler. "@type": "Answer", While it is not important to fully understand the comparison chart, it is good to familiarize yourself with it. In case you havent heard of MERV before, it stands for Minimum Efficiency Reporting Value. },{ Pleats look like an accordion, and can more than double the face area of a filter. An official website of the United States government. Minimum Efficiency Reporting Values, or MERVs, report a filter's ability to capture larger particles between 0.3 and 10 microns (m). MERV and Pressure Drop What Makes the Difference? A thicker filter of the same MERV as a thinner one will usually have a larger face area, a lower resistance to air flow, and less pressure drop. 14 Culprits To Check For Now, MMBTU To MMSCFD Calculator For Natural Gas + Chart, 8 Best Infrared Heaters For Indoors, Patios, Garages (With ECO Thermostats), AGM Battery Voltage Charts: 12V, 24V Deep Cycle Battery Voltage, Lead-Acid Battery Voltage Chart For 6V, 12V, 24V, 48V Batteries, Natural Gas MMSCFD To MMBTU/Day Calculator + Chart, Smoke, dust, oil smell, bacteria, sneeze droplets, Car emissions, bigger dust particles (lead), Legionella, Hair spray, mold spored, mite debris, fabric protector, cat, and dog dander, Pollen, sanding dust, cockroach debris, textile fibers, 85% for 3.0-10.0 m particles, or greater, 90% for 3.0-10.0 m particles, or greater. A MERV Rating indicates a score from 1 to 16 for residential air filters sold in the United States and 17 to 20 for commercial air filters. Frequent filter changeoutsare necessary to reduce the possible negative effects a loaded filter can have on your HVAC equipment. This often coincides with a higher MERV rating; however, this also means that the filter is slightly more restrictive and the airflow rate through the filter is lower. For example, if bacteria ranges from 0.3 microns to 4 microns, the chart indicates a MERV 13 would be the minimum rating to select, and higher MERV-rated filters should be selected with the end users' level of comfort and This chart shows their stated resistance to air flow in inches of water column (IWC/i.w.c.) "name": "How does filter pressure drop affect flow rate? There is a relationship between filter efficiency and pressure drop and resistance. FPR 10 is the same as MERV Ratings 13; MPR vs. MERV Air Filter Ratings. Arrestanceis a measure of the ability of an air filtration device to dust from the air. High MERV ratings are recommended if you seek the removal of allergens from the air as the fibers they are comprised of are layered optimally to trap the smaller-size particles which are generally at fault for triggering symptoms in sensitive individuals. These ratings lie on a scale of 1 to 20. During each cycle a predetermined amount of dust particles is released into the airstream. Use this rating system compare filters made by different manufacturers. This comparison table helps highlight the differences between MERV 8 and MERV 11 filters so it would be easier to decide which one will work best. DC Wire Gauge Calculator: What Gauge Wire (12V, 24V, 48V)? According to this paper, there's a well established connection between higher concentrations of particles in outdoor air and poor health outcomes, so it would make sense that filtering these particles out of indoor air could lead to better health outcomes. Source: www.doityourself.com. Filters with higher MERV ratings trap small particles more effectively than filters with lower MERV ratings. The MERV is a single number that is used, along with the air velocity at which the test was performed, The higher the MERV rating, the more a filter can capture and the cleaner the air will be. The chart below shows the MERV ratings. Get Started With a New Filtration Strategy. However, short of filter neglect, most modern HVAC systems are designed to be able to work with MERV filters in the range of 10 to 13. ", It is not recommended to continue to use your filter beyond its final pressure drop point. "mainEntity": [{ Their rating is based upon filtering out a particular size of air particles, 0.3-micron ones. All air cleaners require periodic cleaning and filter replacement to function properly. They are usually reserved for superior commercial applications. These values are shown to reflect the common vernacular used by many players in the filtration industry, Generally, the higher the MERV (M), you get better filter performance. (1000-3000+ Sq Ft Homes), Thermostat Says Heat On But No Heat? "name": "Does the material affect the pressure drop of the filter? This system is designed by the American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE). While its helpful to know something about the relationship between MERV and pressure drop, it isnt generally something that you should lose any sleep over. A: There is evidence that HVAC operations may help decrease people's exposure to airborne pathogens that spread COVID-19 and other illnesses. ASHRAE stands for the American Society of Heating, Refrigerating, and Air-Conditioning Engineers. Fedder can help you. ; High-rated media is able to retain fumes . Noisy systems when running, high static pressure could be the culprit. This article is not a substitute for review of current applicable government regulations, industry standards, or other standards specific to your business and/or activities and should not be construed as legal advice or opinion. 1-Inch vs 2-Inch vs 4-inch Furnace Filters: Which is Best? ", They require special blowers to pull the air through them. This is how they get the name MERV (MINIMUM Efficiency Rating Value). should be helpful in determining the MERV rating of the filter once the particulate size has been determined. The Air Conditioning Contractors of America assumes that the pressure drop across a . In 2020, the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) recommended switching from MERV 8 filters to MERV 13+ filters in order to help protect against the COVID-19 virus. ", Hi Diane, MERV 20 are highly specialized filters and are not sold online. Other materials used for filters have different MERV and air flow (IR) properties. The ASHRAE paper reviewed studies suggesting that: Use the MERVrating chart below to understand which filters are best for which applications. Because the pleated design creates more surface area, which is a less restrictive design. What is a MERV rating? The higher the filtering efficiency rating (MERV rating), the higher the pressure drop. ASHRAE no longer recognizes MERV 17-20 values. Once the filter is fully loaded the filter will reach its final pressure drop. },{ The higher the MERV, the more efficient the air filter is at removing particles. These filters capture particles at 10.0 microns in size, including pollen, dust mites, and carpet fibers. Typical Applications. Activated carbon filtersremove VOCs and odors. How to Tell if I Should Change Furnace Filter. This is an industry standard rating system. "text": "A filters pressure drop directly corresponds to a filters air flow rate. Refer below to four average contaminant size intervals for MERV rating consideration. The High Capacity MERV 14 Media filter (HC-14) provides a large volume of dust capacity. A numerical chart with values from one through 20 from 1 to 20 measures how effectively the filter stops dust and other contaminants from merv merv rated merv rating merv ratings merv stands minimum efficiency reporting value microparticle performance rating mpr minimum efficiency reporting value mpr mpr ratings range from 1 20 rated rating ratings signify an air filter's effectiveness at reducing airborne particles and contaminants standard 52 5 minimum the minimum efficiency reporting value. "text": "Static pressure is the measurement of the exertion of air flow your HVAC system is moving throughout the system and ductwork." Before we look at the MERV rating chart (1-20 rating for 0.3 10 micron particles), lets answer this question: Do you know why HEPA filters are called HEPA? "@type": "Question", There are a number of factors that determine what the resistance to airflow of a new, clean filter (Initial Resistance, or IR) and the resulting pressure drop will be: 1. "acceptedAnswer": { This will NEVER affect our opinion of a product or service! ", "acceptedAnswer": { Pollutant Size. Since filters with a higher MERV can trap smaller particles, it is often assumed that they will automatically have a greater resistance to air flow.
