In the end, well finally see why HEPA filters are called HEPA (and reveal which filter is even better than the HEPA filter). 1.0-3.0 greater than or equal to 80% "name": "How does filter pressure drop affect flow rate? Hot or cold spots throughout your home? 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. achieves MERV 8 rating before and after a conditioning step Independently tested and verified for quality control Support GridExtremely low pressure drop and high dust holding capacity Construction: We will help you understand your best air filtration options. . Just dont leave it out for more than a day, as we advise in our FAQ post, Can I Temporarily Run My Furnace Without a Filter. M values 1 through 4 are designed to remove large particles. Official websites use .gov ", We recommendMERV 11 filtersas our better air filter. This 4 inch filter has over 60 square feet of synthetic dirt grabbing fibers. MERV 13 Pressure Drop Chart (Click to Zoom). These are the smallest particles that both FPR and MERV-rated air filters will be able to pick up. "acceptedAnswer": { Pressure drop occurs, airflow is reduced and system . To get the right HVAC product and suitable MERV-rated air filter, you should know the area you want to use. Generally, increasing filter efficiency leads to increased pressure drop which can lead to reduced air flow through the HVAC system, more . Cookies Policy. Their cost is often moderate and are within many budgets. Welding fumes and milled flour are this size. "acceptedAnswer": { You can help minimize the risk of HVAC equipment issues or damage from pressure drop, by regularly changing your air filter. "name": "What is the relationship between filter pressure drop and air flow rate? These ratings lie on a scale of 1 to 20. Each air filter has its own unique pressure drop. },{ 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. air). "text": "The pressure drop of a filter is a measure of its resistance to airflow through it. Thats why air filter producers dont usually specify the MERV rating. Remembering to change your air filter is key to reducing the risk from pressure drop. "@type": "Answer", MERV stands for Minimum Efficiency Reporting Value. "name": "What are the signs of unhealthy static pressure in an HVAC system? It is an acronym for "high efficiency particulate air [filter]" (as officially defined by the U.S. Dept. Why? As a result, we cannot show you the price in catalog or the product page. The lower the pressure drop the easier it is for air to flow through the filter. Industrial HVAC air filters are installed in commercial HVAC systems to remove airborne contaminants from the air stream. ", This level of filtration does fall into the MERV system but they are shown here to add continuity to the overall filter picture. For example, a 4-inch-thick MERV 12 filter can have a 0.2-inch WC pressure . depth MERV 13 filters are available with pressure drop characteristics comparable to or lower than some MERV 6 filters, staff also finds that a 2" filter depth is valuable in allowing filters to have airflow characteristics that are superior to a 1" filter, and may facilitate use of even higher MERV filters (such as the MERV 16 recommended by PICKHVAC Terms of Use: Some of the products seen on our site are delivered through a relationship with outside suppliers like Networx.com, Google, and others. The final pressure drop/final resistance is measured when the filter has reached its total dust holding capacity and is ready to be replaced. Weigh the test filter. The Air Conditioning Contractors of America assumes that the pressure drop across a . } Hi, great article! It is a rating system incorporated into the test specification of ASHRAE 52.2. The vertical axis shows system static pressure drop by 0.1 inch w.c., and across the horizontal axis it shows system air flow in cubic feet per minute (CFPM). The more tightly woven or thick a filters media is, the more particles and contaminates the filter can trap." Our Complete Recommended MERV Rating Guide is a good source for understanding the best filter for your HVAC system. E2 arrestance is for the middle size particles. This helps improve indoor air quality and prevents the build up of contaminants in equipment and damaging it. } Use this rating system compare filters made by different manufacturers. Yes, really! The higher the MERV rating the more efficient the filter is at filtering out and capturing air particles and contaminants. The pressure drop across an air filter will determine how negatively the filter affects airflow. 2. 99.97% or better for all particle sizes). We cannot assume that the two AHUs operate at the same airflows, so the costs normalized for airflow are best used to make an estimate of annual energy savings by using 5-Star air filters. The chart displays the static pressure drop curves for filters at four MERV ratings. . 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. The resulting rating is theen given to each filter. "@type": "Question", Typical MERV 11 Filter 3M MERV-11 3M MERV-14 How Our Filters Perform Over Time This chart shows how our media performs over time as a 20" x 25" filter collects particulates as measured at different air volumes. Pressure drop is defined by the National Air Filtration Association (NAFA):The pressure drop of a filter is a measure of its resistance to airflow through it. It shows particle size ranges. Does the airflow significantly improve? ), CO2 Heat Pump Water Heaters Vs. Resistive Hot Water Heaters, MERV 13 Filter Pressure Drop: Guidance for Facility Managers, Free Tool to Measure the Air Changes Per Hour of Your Space, Mitigating the Impact of COVID-19 on Small Businesses By Improving Indoor Air, The In-Depth Guide to HEPA Filters in Hospitals, Medical Offices, & Clinics, Reopen Safely and In Compliance with NYS Mandates, Measure Your Spaces Air Changes Per Hour, https://www.rpfedder.com/filtration/merv-13-filters/. } air), Latent Heat (BTU/hr) = 0.69 x CFM x gr. 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. "text": "Filters use various types of medias depending on the application or what the environment requires. Estimated energy cost reduction from high capacity air filters, normalized for airflow: ($0.463/cfm $0.575/cfm) / $0.575/cfm = -19.5%. Share sensitive information only on official, secure websites. The following example illustrates how this can play out for a hospital investing in higher quality filters to reduce their energy and filter replacement costs. The MERV 5 is an excellent entry into the pleated filter lineup because it is low cost, readily available, and will . The Back pressure from this filter is 0.22 WG. Because they go off the MERV chart, they are referred to as HEPA filters or high-efficiency filters. Products and solutions to help your business move forward. The ASHRAE paper reviewed studies suggesting that: Use the MERVrating chart below to understand which filters are best for which applications. "name": "Do higher MERV rated filters restrict air flow? Pressure Drop inches w.c. Pressure drop directly corresponds to a filters air flow rate. Frankly, that can happen with about any filter higher than a MERV 5 if it gets dirty and clogged. Average Particle Size Efficiency in Microns, 1.0-3.0 greater than or equal to 20% The poorest performance is used. It is a measure of a filters ability to trap particles in the air. OK ! Other materials used for filters have different MERV and air flow (IR) properties. This is important to consider when choosing a filter for your application and your HVAC unit. In general, filters with a rating of MERV16 or below are considered to be HVAC-system-grade filters for residential, commercial and general hospital use. Weve identified that there is an increase in pressure drop and energy costs when switching to MERV 13 or higher filters. "@type": "Answer", The amount of the HVACs air flow slowed by the filter is equivalent to the filters pressure drop. These dust particles fall into three size groups. SEER = (1 EER100% + 42 EER75% + 45 EER50% + 12 EER25%)/100, Total Heat (BTU/hr.) Calculator + Chart (Natural Gas), Average Gas Bill For 1-Bedroom Apartment: State-By-State Cost Analysis, Average Electricity Bill For 4 Person Household (Survey Analysis), How Many kWh Per Day Is Normal? "name": "What is filter pressure drop? Minimum Efficiency Reporting Values, or MERVs, report a filter's ability to capture larger particles between 0.3 and 10 microns (m). So, whatever air filtration you choose, be sure it includes a carbon filter. MERV Rating Chart Understanding MERV Ratings All filters have a MERV rating that falls between 1 and 16. At the lower end of the efficiency spectrum a fiberglass or polyester panel filter may have a MERV of 4 or 5. However, if you are trying to filter out COVID-19 virus, they call for a MERV 13 or as high as your system can accommodate. Woodhead Publishing, 2017. "@type": "Answer", Since MERV 13 filters (https://www.rpfedder.com/filtration/merv-13-filters/) are on the higher end of the rating scale, they can be susceptible to excessive pressure drop. No representation is made that the information or references are complete or remain current. It ensures reliable and consistent testing of air filter performance. },{ Includes a moisture resistant, high wet-strength beverage board frame. LakeAir replacement filters use 4 different MERV rated filters. Fiberglass and washable filters are typically 1-4 MERV, and can filter out particles of 10 microns and larger. Their rating is based upon filtering out a particular size of air particles, 0.3-micron ones. MERV rating ranges between 10 and 12 are suitable for removing a broad range of particles. ASHRAEdeveloped the MERV air filter efficiency rating system. The lower the pressure drop the easier it is for air to flow through the filter." "acceptedAnswer": { Estimated energy savings from 5-Star filters per AHU, extrapolated to annual basis (assuming 24/7 AHU operation, 34,235 cfm airflow per AHU): ($0.463/cfm $0.575/cfm) x 34,235 cfm = $3,834 annual electric energy savings per AHU. MERV ratings are derived from the ASHRAE 52.2-2012 test which groups the particles sizes into three categories. Two 14X14 filter grilles are way too small. Do a quick search online using MERV in your question and youll see statements such as, Higher MERV means higher pressure drop. OR Higher MERV filters can destroy your HVAC system. These statements are presented as set-in-stone, hard facts that are not to be refuted. Always refer to your air handler manufacturers guide before changing your air filter. Particles that are larger or smaller are trapped with even higher efficiency. February 2022. Filters with higher MERVratings trap small particles more effectively than filters with lower MERVratings. What are the benefits of a higher MERV rating? MERV rating. ", What are they and why they matter? 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. Install the test filter in the test duct and obtain clean air filter resistance or initial pressure drop. While that can happen, it most likely will not be a result except under extreme circumstances involving a cheap blower motor and the concern addressed below. Some pleated filters with the same or lesser MERV's have higher pressure drops. Q&A Debunking Myths About MERV, Air Filtration . You can check the whole EPAs list of air pollutants here. 2. This is an industry standard rating system. Each filter is assigned a rating based on how much debris a filter manages to block when circulating air. When used as final filters, they are the primary filters for an HVAC system. Its actually based on the MERV rating. Generally, filters with higher MERV ratings have less airflow. They are not Minimum efficient. } The blowers in HVAC units rely on a good air supply to keep them cool. The furnace filter frames use a M 10 rated level air filter. Will it burn up your HVAC system? Hi Diane, MERV 20 are highly specialized filters and are not sold online. ", Weve also posted one of the popular Pick HVAC FAQ guides on Signs the Filter Needs to be Changed that addresses related topics. The accepted pressure drop is different for each air conditioning or air handling system, and you should always refer to your manufacturers guide prior to inserting replacing your air filter to ensure you are using the appropriate filter. Likewise, the mid-MERV filters also showed decreased air flow relative to the low-MERV filters, this time 3% and 8% lower in the two systems. 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. } Where to find MERV and IR: This information is printed on the edge of the frame of the filter and can be seen before you purchase it. That will definitely increase the pressure drop and place unwanted strain on your HVAC system. Surface area of the filter. MERV, which is an acronym for Minimum Efficiency Reporting Value, is a rating system that was developed by ASHRAE (the American Society of Heating, Refrigerating and Air-Conditioning Engineers). The High Capacity MERV 14 Media filter (HC-14) provides a large volume of dust capacity. How efficient the filter is against all three size ranges is compared against a MERV chart and the final MERV value is the highest value where the filter meets all three requirements of MERV. Check your filter at least once a month for dust buildup. They specify a minimum MERV of a filter to use, but not the IR. HEPA and ULPA filters are represented in the 17 through 20 ratings. Spun fiberglass almost always has a lower IR than other materials. The most prevalent MERV ratings are MERV 4, 6, 8, 10, 12, 14, and 16: A Higher MERV rating automatically means a better filter. If I look at AprilAire's CFM table per product, it shows the following pressure drops in order from the 410, 413, and 416 models (i.e. in the Inch-Pound system of measurement. In case you havent heard of MERV before, it stands for Minimum Efficiency Reporting Value. MERV ratings 1 to 4 are generally only used as pre-filters but can be found in many typical applications like commercial buildings, furnaces, and window AC units. The filters initial pressure drop (initial resistance) will vary by the filter type, MERV rating, and size. This also means that as the MERV rating goes up, the more particles and contaminants the filter can capture. Every air purification system should have an activated carbon filter. This Standard is what led to the creation of the minimum efficiency reporting value, or MERV. Guaranteed against media pack failure to 5.0 w.g. Minimum Efficiency Reporting Values, or MERVs, report a filter's ability to capture larger particles between 0.3 and 10 microns (m). "@context": "https://schema.org", 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. Filters use various types of medias depending on the application or what the environment requires. "name": "Does air filter pressure drop change? "name": "What is static pressure? }] Typically, the higher the MERV rating, the higher the pressure drop and the more restrictive the air flow is. 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. LakeAir provides discounts to Veterans, First Responders, and the Elderly. This is one way a higher MERV filter can have a lower pressure drop than one with a lower MERV rating. When selecting the right filter for your application, higher is not always better. Inexpensive and energy-efficient. Most current home HVAC units can accommodate a filter with a MERV 13 or lower. 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. Frequent filter changeoutsare necessary to reduce the possible negative effects a loaded filter can have on your HVAC equipment. The range is from 1 (lowest efficiency) to 20 (highest efficiency). They are usually reserved for superior commercial applications. These air filters are great for people with pets. If the light is significantly blocked, install a new filter. The MERV rating system goes from 1 to 16, with the higher numbers representing filters that can remove smaller particles from the air. Airflow through the vents is lower: Is the new filter causing low airflow? When your HVAC system is running the filter slows and limits the air that is being pulled through your vents and ducts. As you can see above, research shows that in general, HVAC systems with high MERV* filters have a higher pressure drop across the entire filter. The majority of residential HVAC systems use a 1" thick filter, but filters are available at 2", 4" and 5" thick. } For comparison, a grain of sand is about 60 microns. This method tests Air-Cleaning Devices for dust removal efficiency. The manometer below shows my reading across one of the clean MERV-13 filters. "acceptedAnswer": { Actual Size: 23-3/8 x 23-3/8 x 3-3/4. A: There is evidence that HVAC operations may help decrease people's exposure to airborne pathogens that spread COVID-19 and other illnesses. Typically, the higher the MERV rating, the higher the pressure drop and the more restrictive the air flow is. Hot or cold spots throughout your home? When choosing a filter, remember that airflow (pressure drop) is just as important to consider as filtration (MERV rating). A MERV rating chart shows a numerical value. In fact, some MERV 8 and MERV 9 filters have similar or higher pressure drops than the MERV 13 filters. The performance ratings given above are adapted from equivalent EU and MERV ratings and test classifications for filters as outlined in AS1324.1, EN779 and ASHRAE52. A MERV rating is a numerical rating system developed by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) to rate the effectiveness of air filters. Just make the filter bigger and you get a lower pressure drop. } In other words: HEPA filters are better than anything MERV rating can measure. The test duct fans can operate up to a speed of 750 fpm. These filters capture particles at 10.0 microns in size, including pollen, dust mites, and carpet fibers. You can check the best medical-grade air purifiers here; these use H13 HEPA filters. All filters will increase in pressure drop in use. Green Manufacturing ~ How green is your air purifier? The informed consumer is a powerful force in the marketplace. We are hiring! They remove pet dander and most allergy causing air particles. Brown and Christopher L. Cox, eds. Higher MERV But Lower Air Resistance Can Happen. "@type": "Question", I know you're dying of the suspense now, so here are all the measurements. Their average efficiency from 3 to 10 micron is less than 20. P.S. M 10 filters are easy on air blowers and fans. The rating was devised by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) to answer one question: Which air purifier is the most effective? What was their secret? From ASHRAE Journal Newsletter, December 8, 2020 . "@type": "Question", The Velocity (speed) of the air flow is tested at 1 of 7 different speeds. Please click here to see any active alerts. For example, a household pleated filter that uses synthetic media will have a lower pressure drop than a micro-fiberglass media that is used in critical environments such as a hospitals and datacenters. When a particle is in the 0.3 to 1 micron in size it is considered microparticle. 1-Inch vs 2-Inch vs 4-inch Furnace Filters: Which is Best? DC Wire Gauge Calculator: What Gauge Wire (12V, 24V, 48V)? 1.0-3.0 greater than or equal to 90% When youre buying an air purifier for a specific purpose, you need to know how big the air contaminants youre looking to remove are. Improved indoor air quality by capturing more particles, a higher MERV rating results in cleaner air being circulated throughout the home or office. { ASHRAE stands for the American Society of Heating, Refrigerating, and Air-Conditioning Engineers. Many of our competitors claim read more. Need more details? ", "name": "Does the material affect the pressure drop of the filter? Thick and high-MERV filters can cause a significant drop in pressure inside your HVAC system from before to after the filter. "@type": "Answer", The performance is based on particles that are 0.3-10 micron in diameter. The scale rates how well a filter removes fine particulates from the incoming air. You can also reach us by phone at (585) 288-1600 or send an email to hello@rpfedder.com to get started. MERV stands for Minimum Efficiency Reporting Value. If a system is designed with a standard filter for that pressure drop, the pressure drop with a pleated filter of the same size will most likely be higher. Weve got em. The higher the number, the better the filter is at capturing larger particles between 0.3 and 10 microns (m).