Find quick, clear answers to some of our most frequently asked questions about our products, industry, and company.
Rensa Filtration is dedicated to transforming air quality. Our manufacturing side creates a wide range of air filters, from high-level MERV filters to specialized carbon-based products that prevent corrosion. Our EFP (Engineered Filtration Products) partner with you to create truly custom solutions, visit our Custom Design page. We also offer nation-wide distribution, servicing coast-to-coast.
We’re not just suppliers; we’re strategic partners in air quality. With a fearless drive for innovation, we deliver industry-leading products and solutions, ensuring seamless service so you can focus on what matters most: your business.
To learn more about what makes us and our products different, visit our Why Rensa page.
Clean air is a universal right, and Rensa serves many industries to ensure it. We provide advanced air filtration solutions for Airports, Automotive & EV, Clean Rooms, Commercial, Data Centers, Food & Beverage, Healthcare, Life Science, Power Generation, Semiconductor, Shooting Ranges, Swine or Poultry and more. Don’t see your industry listed? Reach out and we’d be happy to work with you.
Rensa products are designed to fit industry standards such as ASHRAE and ISO test methods, with performance verified through our internal labs. We focus on consistent manufacturing, traceability, and ongoing quality control so customers can rely on the filter's operation.
We believe in the power of collaboration and growth. If your company is dedicated to innovative air filtration solutions and interested in merging with or being acquired by Rensa, we’d love to connect.
Air filters trap dust, pollen, mold spores, and other airborne particles, keeping your air clean and healthy. We have many other filter types that specialize in different applications - ranging from odor and gas to paint overspray, and from pathogens to grease. See all of our products.
Regular maintenance is key. Check your filters monthly and replace or clean them every three to six months, depending on usage and environmental factors. Need support or a consultation from one of our many filtration experts? Contact us.
Maintaining air filters ensures optimal air quality for your facility, extends HVAC system life, and improves energy efficiency, keeping your environment safe and your operations smooth.
Visit our Sustainability section to learn about our product capabilities and impact.
There are a few telltale signs that your filters need to be cleaned or replaced:
You see more dust buildup throughout your facility.
There is a spike in your energy bill.
Your air filters are coated in dust, dirt, and other pollutants.
Your AC/Furnace takes longer to heat or cool your facility.
Investing in high-quality air filters extends their lifespan, reducing the frequency of changeouts. Depending on the filter, they can last up to three to five years with proper pre-filtration, such as our PreVent® air intake filter. This longevity means maintenance teams spend less time replacing filters, especially those on rooftop units, and can even reduce frequency and time spent on equipment cleaning.
Ongoing checks suffice, but changeouts might not be needed for several years, significantly saving labor time and costs, allowing personnel to focus on more critical tasks and responsibilities.
Neglecting to change your air filters on time can lead to clogged filters, restricting airflow. This results in poor indoor air quality and increased energy consumption as fans work harder to regulate building temperature. Additionally, clogged filters can cause filter blowout, leading to significant issues downstream in the system and critical downtime that you can’t afford.
Regular maintenance is crucial to ensure efficiency and maintain air quality. Following regular maintenance, your filters are prepared to last longer. Filters that endure a long life-cycle lead to reduced cost of operations.
Filters add resistance to airflow, and fans must work harder to move air through them. The industry focuses on balancing efficiency (how much particulate is removed) with pressure drop (how hard the fan has to work) so facilities operate without using excess fan energy, changeout labor, or downtime.
Learn how Rensa integrates sustainability to reduce energy use and costs.
Key trends include higher IAQ expectations, wider adoption of higher‑efficiency/MERV filters, more attention to lifecycle total cost of ownership.
Industry-wide there is a growing demand for application‑specific solutions—such as data centers, cleanrooms, healthcare, and high‑risk industrial environments—rather than one‑size‑fits‑all products.
Learn more about current topics with our case studies.
Yes, many of our filters are covered under our UL certifications. If you have questions about the certification of a specific filter, please contact us and we can provide that information.
MERV stands for Minimum Efficiency Reporting Value and measures a filter’s efficiency. Higher MERV ratings indicate better filtration of smaller particles, ensuring cleaner air. You can view our products by this rating: Product Search.
HEPA stands for High-Efficiency Particulate Air. These filters capture 99.99% of particles as small as 0.3 microns, providing superior air purification. Explore our range of HEPA filter products.
Our HEPA filter material contains advanced synthetic or fiberglass media engineered to capture the smallest airborne particles. The choice of material depends on application requirements, operating conditions, and compliance standards.
When you order a HEPA air filter from Rensa Filtration, you get the advantage of:
Longer filter life and reduced maintenance downtime
Consistent airflow and energy-efficient operation
Lower risk of contamination in sensitive spaces
Flexible designs, including V-Bank HEPA filters and housing HEPA filter options
Technical expertise to guide specification and installation
Pleated filters are typically made of paper, cotton, or polyester and have a folded surface to increase filter area, improving dust-holding capacity and maintaining airflow efficiency. Explore our range of pleated filter products.
Service life depends on air quality, system usage, and MERV rating, but most pleated HVAC filters should be replaced every three months. Rensa’s heavy-duty and high-capacity models are designed for longer intervals in busy facilities.
For most commercial and residential systems, MERV ratings of 8–13 are suitable. Environments that require finer filtration, such as healthcare, laboratories, or cleanrooms, benefit from higher-rated mini-pleat air filters in the MERV 14–16 range.
Depending on your facility requirements, a higher MERV rating might be what you need. Find the right filters for your facility using Rensa's resources section.
By analyzing the appropriate efficiency, configuration, and change‑out schedule, Rensa filtration systems can support IAQ and ventilation guidelines. Organizations like ASHRAE require you to follow any relevant building or health codes.
On our website, you can find which requirements are needed for your facility. View our wide catalog of filtration products.
Rensa can help compare options by looking at pressure drop, expected service life, energy consumption, and change‑out labor. This allows you to choose filters that balance operating costs and system reliability over time, rather than focusing on initial cost alone.
Learn how Rensa manufactures a product that minimizes your total cost of ownership. To reach out about your HVAC and filtration inquiries, contact us.
Most Rensa products are supported by technical data sheets and, where applicable, third‑party or internal test reports that document performance characteristics. Reported metrics fall under efficiency, pressure drop, and recommended operating conditions.
At Rensa, we believe in incorporating traceability and ingenuity into our filtration products. Our customers will benefit from reliable filters that perform at the highest level.
Rensa products are available through a network of distributors, OEM partners, and select direct channels. If you’re unsure where to buy, contact us and we’ll connect you with the appropriate sales or distribution partner for your region and application.
Click to view an extensive list of our product offerings.
Yes. Just a few cottonwood seedlings wouldn’t seem to do a lot. But each cottonwood tree can release more than 25 million seeds a year, and seeds can travel up to five miles away. So you can imagine what sort of trouble all that cottonwood can do to a rooftop HVAC unit.
A cottonwood screen not only protects units from cottonwood but from all sorts of debris including leaves, dirt, seeds, insects, dust and pollen. They prolong equipment life, help you save considerable maintenance and cleaning costs, and reduce energy consumption (and utility bills). By making HVAC equipment work better and more efficiently, cottonwood filters also ensure cleaner air which can improve employee productivity and health, and keep computer equipment performing better and lasting longer.
No. Independent laboratory testing* showed that PreVent equipment protection filters cause less than 1% change in compressor discharge pressure, resulting in negligible performance degradation due to pressure drop. Tests were run on a clean condensing unit and repeated with a PreVent single layer filter surrounding the unit to determine what change in unit performance might occur. It was the intent of this test to verify the type of changes that occur as debris loads and air flow is diminished.
* ARI Standard 210-240-2006 Performance Rating of Unitary Air Conditioning and Air Source Heat Pump Equipment Underwriters Laboratories, Plano , TX.
Yes. Because cottonwood is such a significant problem in some areas, many people refer to the product as a “cottonwood screen” or a “cottonwood filter.” Because the screen fits over an air intake opening, they are also commonly referred to as an “air intake screen” or “air intake filter,” particularly in areas where cottonwood is not a significant problem.
Our PreVent air intake filters are custom-made and so can fit any air intake, no matter how big or small. We can design them to fit into any shape or size, including around pipes or other obstacles. We offer multiple model options for the PreVent filter, with a number of mount options, depending on your application.
Not at all. PreVent air intake filters have been designed and tested for their low resistance to airflow and lack of interference with equipment performance when properly installed and maintained.
We use third-party testing to verify the effectiveness of our PreVent air intake filters. In fact, independent testing has shown that using a PreVent air intake filter causes a less than 1% change in compressor discharge pressure.
PreVent air intake filters can be installed in just minutes with our patented MagnaMount® earth magnets, or magnetic strips. No tools or drills are needed, and the air intake filters are simply snapped into place. The magnets are strong enough to keep the cottonwood screen in place even during the windiest conditions. They can also be removed for cleaning, or to access the inside of HVAC equipment, just as easily and quickly.
Your frequency of cleaning depends on the environment around you, and the time of year. For example, cottonwood trees can lose their seedlings from May through October. During the worst of the season, you may want to check the screen every week or two, although typically you can check it less often.
Since PreVent air intake screens can simply be brushed down, in place, you won’t need any downtime to clean them. You can also vacuum or clean them with a hose.
If you clean them with a high-pressure hose make sure you remove the screens first, to avoid damaging the fins behind them.
Yes, but not as often. One of the main advantages of a cottonwood screen is keeping your coils clean, which lessens the need for frequent cleanings. Customers of our PreVent air intake filters typically save 25% or more in their coil cleaning costs alone.
Just make sure you install your cottonwood screens over a clean coil! Clean coils are important to ensure long and optimal HVAC equipment performance. According to EPA research, just 0.042″ of dirt on an air conditioning coil can reduce its efficiency by 21%. Dirty coils can increase energy and cleaning costs by more than $22,000 a year per unit!
Not only is polypropylene a hardy, sturdy material that can withstand the rigors of a rooftop environment, but polypropylene is also resistant to abrasion, most acids, alkalis, bleaches, solvents, aging, corrosion, high-velocity airflow, and industrial cleaning and maintenance.
Yes, our PreVent filters, like many of our filters, come with a 5-year warranty.
Activated Carbon is a material that has been treated (activated) to increase the internal surface area of the structure to the range of 950 to 1150 square meters per gram for gas phase applications. The internal area is the area that holds the adsorbed chemicals; in effect, this is where the “work” is done. Explore our range of carbon filter products.
Activated carbon ADSORBS a wide variety of gases and vapors – chemical pollutants. Whether there is one gas molecule and one carbon particle, or many of each, the adsorption process is the same. The physical process begins with a gas molecule coming into contact with the surface of an activated carbon particle and coming to rest in a large surface pore. Then, due to unbalanced forces on and within the carbon particle, the gas molecule will begin to move “down” into the carbon particle – into the smaller pores, where it will finally stop and be held in place. At some point between the surface and the “stopping point”, this gas molecule will condense and become a liquid particle.
The adsorbate diffuses thru the surface film to the macropore structure. Then, due to van der Walls’ forces, the gas molecule migrates into the micropore structure, condensing during this movement, and finally stopping when either the forces become balanced or it becomes physically blocked. This molecule, which was an objectionable gas, will remain a liquid inside the carbon until it receives enough energy, in the form of heat, to excite it. If this condition arises, the molecule will begin moving toward the surface. If enough energy (heat) is absorbed, it will be vaporized, returned to a gas and be released back into the air stream, i.e. the process will be reversed. In HVAC applications, there is normally not enough heat to excite, or re-energize, adsorbed molecules. With regular carbon filter or bulk carbon “changeouts”, sufficient capacity will always be available. It is interesting to note, the adsorbed gases that condense and become liquid molecules will “line” the internal surface area – and this “lining” will be one (and only one) molecule thick.
Theoretically, we can remove almost all particulate matter from the air stream. We are now faced with “how should the gases and vapors—the chemical pollution—be removed?” HEPA filtration is effective down to the 0.3 micron range and will remove some particulates smaller than 0.3 microns. Gases and vapors are 0.01 microns and smaller. Benzene and naphthalene, two compounds that are strongly adsorbed by carbon, are approximately 0.0006 and 0.0007 microns respectively. One micron equals 1/25,400 of an inch.
Particulate filters do not, and can not, remove material that is this small and is a gas. If particulate means cannot be used to remove gases, then how can they be removed? For HVAC applications, where the concentrations are very low and the contaminant loading varies constantly, adsorption has proven to be the most effective and the most economical process.
Adsorption with activated carbon is also the process of choice for applications such as gas masks, space capsules, nuclear submarines, and radioactive iodine removal (nuclear plants). Are there other processes to remove gases from an air stream? Certainly, when higher concentrations are present, incineration, chemisorption, and solvent recovery (an adsorptive process) all have their places. Explore our range of carbon filter products.
The term CHARCOAL is used widely, and the question often asked “What is the difference between activated carbon and activated charcoal?” There is only one material, and the terms are used interchangeably. Those who are in the carbon business will use the term carbon, and those outside the industry, or just learning, will use the term charcoal. ASTM – The American Society of Testing Materials – utilizes the term carbon.
Carbon filters are used in buildings and environments where odors, gases, fumes, or airborne chemical pollutants need to be removed from the air. Unlike particulate filters, carbon filtration targets gaseous contaminants such as VOCs, ozone, nitrogen dioxide, sulfur compounds, and smoke-related odors.
They are commonly required in both occupied spaces and mission-critical environments, especially where air quality impacts health, comfort, equipment reliability, or regulatory compliance.
Common building types and environments that benefit from carbon filtration include:
Healthcare & Life Sciences
Hospitals, clinics, nursing homes, and assisted-living facilities
Medical laboratories, research labs, and cleanrooms
Veterinary hospitals and animal care facilities (Used to control chemical odors, disinfectant off-gassing, anesthesia byproducts, and patient comfort concerns.)
Commercial & Institutional Buildings
Office buildings, corporate campuses, and municipal buildings
Libraries, museums, and archives
Schools, universities, and childcare facilities (Used to reduce outdoor pollution infiltration, occupant complaints, and persistent indoor odors.)
Transportation & Public Facilities
Airports, transit hubs, and train stations
Stadiums, arenas, auditoriums, and convention centers (Used to manage high occupant density, vehicle exhaust infiltration, and external pollution sources.)
Industrial & Technical Spaces
Data centers, computer rooms, and electrical rooms
Microelectronics manufacturing and precision environments
Clean manufacturing and controlled process areas (Used to protect sensitive equipment from corrosive gases and airborne chemicals.)
Retail, Hospitality & Food Service
Restaurants, commercial kitchens, and food courts
Retail stores, shopping centers, and mixed-use developments
Hotels and hospitality spaces (Used to control cooking odors, waste odors, and customer-impacting smells.)
Specialty & Odor-Generating Environments
Print shops, fabrication areas, and light manufacturing
Waste handling areas and loading docks
Pet groomers, kennels, and animal shelters
Wildfire-Prone and High-Pollution Regions
Buildings located in wildfire-affected areas
Urban locations with traffic exhaust, industrial emissions, or seasonal smoke events (Carbon filters help remove smoke odors and harmful gases associated with wildfire smoke, improving indoor air quality when outdoor air is compromised.)
In short: Any building where outdoor air quality is unpredictable, indoor odors are persistent, or gaseous contaminants pose a risk to people, processes, or equipment is a strong candidate for carbon filtration.
Carbon filters are often deployed as part of a multi-stage filtration system, working alongside particulate filters to deliver cleaner, healthier, and more controlled indoor air.
There are many types and grades of carbon that can be used for adsorption. There are carbons used for liquid and gas phase applications; they are not interchangeable. For the purpose of this presentation, only gas phase carbons that are used for general HVAC applications will be addressed. The commercial quality HVAC carbons that are being manufactured today are produced from either coal or coconut shells. These materials are interchangeable, as long as the activity level and the average particle size are the same.
The application of carbon to HVAC installations is considerably different when compared to how carbon is applied to solvent recovery systems and other industrial removal applications. For the latter, air streams with hundred to thousands of parts per million (ppm) of gas molecules are recovered, or removed, with beds that can be several feet thick and contain thousands of pounds of carbon. For HVAC applications, thin bed filters with comparatively small amounts of carbon are utilized. Therefore, it is not only important that these differences be recognized, but that the parameters be defined.
First, air in a structure can be treated as it:
Enters.
Leaves.
Is re-circulated.
Or a combination of the above.
For the majority of HVAC applications, the air to be treated is a combination of air entering (make-up) and air that is re-circulating. The gaseous contaminant loading that should be removed:
Is always a combination of many odors and pollutants – chemicals.
Is normally unknown either as to the chemical make-up, the amount of each pollutant, or the total loading.
Varies constantly with changes in occupancy levels, activity within or without the structure, and shifts in the wind.
Is in the 1 ppm range.
As stated earlier, activated carbon, the universal adsorbent, will adsorb “some of almost any vapor”. Detailed lists of gases and vapors – chemical compounds – are available from carbon and equipment manufacturers. The following is a partial list of gases that are of concern in the air purification systems and can be removed with carbon:
Organic Compounds: Acids, Alcohols, Aldehydes.
Chlorinated Hydrocarbons: Esters, Ethers, Ketones, Mercaptans, Amines.
Inorganic Compounds: Halogen Acids, Halogens, Sulphuric Acid, Sulphur Dioxide, Phosgene.
Miscellaneous Odors From: Humans, Animals, Foods, Cooking, and Waste Processes.
The carbon adsorption products that have been designed and utilized for HVAC applications are very effective. When they are misapplied in industrial applications, problems can and do arise. Normally, it is not that the carbon does not adsorb, but rather the concentration exceeds the capability of thin bed products, and neither the pass efficiency nor the life (capacity) are satisfactory. Industrial applications, although they will contain many of the same chemicals found in HVAC applications, can be defined as having:
Primarily one contaminant (chemical).
A chemical that is known, both as to it’s formulation and quantity (ppm).
Either a constant quantity or a constant range.
A loading well above the 1 ppm range.
Very simply, this will be, by comparison, a heavy-duty application, and the information concerning the contamination will be known. One example that will crystallize the differences between these applications: A printing company with a large printing press may have a solvent recovery system to recover the solvents from the inks. This system will remove the high concentrations of solvent with large amounts of carbon. However, the solvent “leakage” that escapes into the general air and into the air handling system will be heavily diluted and be just one of the many other chemicals in the HVAC system. This air, that re-circulates thru the offices, lunchrooms, laboratories, etc., would now be treated as an HVAC application, with thin bed products. Adsorption may not be the most effective process for industrial applications. Companies skilled in these fields should be consulted to make the determination regarding the most effective process and system.
Absorption can be understood if we think of sugar being dissolved in water and mixing evenly throughout or cream being mixed into coffee. Industrial absorption would be a gas being absorbed (taken into and mixed evenly) by a “scrubbing” liquid. In contrast, adsorption is the physical attraction and adherence of gas or liquid molecules to the surface of a solid. The attractive force is very small, van der Waal’s forces, and exists between any two bodies, such as between the earth and the moon. Gas molecules are adsorbed by activated carbon. Explore our range of carbon filter products.
Activated carbon is truly a unique material. There are no other materials, natural or man-made, that will do all that it will do. Activated carbon:
Has a capacity for virtually any vapor contaminant; it will adsorb “some of almost any vapor”.
Has a large capacity for organic molecules, especially solvents.
Will adsorb and retain a wide variety of chemicals at the same time.
Has an extremely large capacity to catalytically destroy ozone, a major component of smog.
Works well under a wide range of temperature and humidity conditions.
Adsorbs odors and chemicals preferentially to moisture. It is not a desiccant and will release moisture to adsorb chemicals.
Can be used as a carrier of one material to attract and hold or react with another material.
Is inert and safe to handle and use.
Is available and affordable.
Activated carbon will adsorb without the air being drawn thru it, i.e. without a fan or blower. This is of importance when there are rooms or closed areas that do not have ventilation ducts, electricity and/or where the use of a portable air cleaner would not be practical. Carbon pads can be placed in these areas and be a very effective solution. Gas molecules will disperse (mix) themselves evenly throughout a given area, in accord with the “Perfect Gas Laws”.
Activated carbon will attract and adsorb the odor or pollutant molecules to which it is closest, causing an unequal mixture to result. Whereupon the gases will redistribute themselves, the carbon will again adsorb the closest, and the process will continue until the air is “cleaned” or the carbon reaches its capacity. A relatively small amount of carbon can, and will, keep these types of areas odor and pollutant free. An example of utilizing a small amount of carbon is to maintain a refrigerator odor free. By adsorbing gases, it thereby eliminates the transfer of odors and tastes from one food to another, and to ice cubes.
When the loading drops below 1 ppm, down to the ppb [parts per billion] or to the .1 ppb range and below, there is no concern. When the loading increases, which it can do for short periods, there are concerns and questions.
Knowing that the industry has utilized, and continues to utilize, thin bed carbon filters, the following situations must be considered:
How high are these higher loadings (peaks), and how long do they last? Unless the structure has been studied over a period of time, there is no definite answer. Ten to 20 ppm would be a heavy overload and may be within reason for this application. This condition may last for minutes to hours as opposed to days.
During the peaks, how effective is the filtration system? The percentage of these peaks, which exceeds the design capability of the filter or the capacity of the carbon at that time, will pass thru and into the inside air. Since the air is being re-circulated, these peaks will be adsorbed on future passes. As stated earlier, carbon must be changed on a regular basis. This regularity, which should be established during the first year of operation by utilizing test samples, will insure that these peaks, typical to that installation, will be quickly adsorbed.
For HVAC applications, adsorption products can be divided into several categories:
1. Panel Filters: Panels filters are available in a variety of designs and configurations. They are available in a variety of thickness’, 1″, 2″ and 4″, with 2″ being the predominant commercial product.
Panel filters can in turn be divided into two groups:
A. The newer products: Carbon filter products that are designed to have a low pressure drop and are normally interchangeable with particulate filters. Filters using either pads or pleats, contain either granular or powdered carbon. Carbon is either integrated with fibers during manufacturing or impregnated via a slurry process into an existing non-woven product. For 2″ filters, in either pad or pleat form, carbon loadings will vary from approx. 300 grams per square foot of filter face area, down to about 35 grams per square foot. Products include, three stage filters, pads, pads in die cuts, pleats and ring panels.
B. The older products: Filled or honeycomb filters have relatively high pressure drops and therefore can not be interchanged with particulate filters. They are utilized in V-banks. Filled filters have perforated metal faces, held in place with welded metal spacers, surrounded with a metal frame and filled with carbon. Honeycomb filters utilize a honeycomb shaped material as the internal structure, which is either partially or completely filled with carbon. The carbon is contained within the honeycomb structure by a thin netting and a metal frame which surrounds the structure. As filters, they are available in ¾”, 1″ and 2″ thickness’. When used in V- banks, the ¾” and 1″ “trays” account for almost all HVAC applications. The 2″ thickness is used only in special applications. Both filters contain packed granular carbon. Loadings vary from approx. 2.1 lbs/sq. foot of filter face area for a 1″ filled filter, to slightly under 1 lb/sq. foot for a ¾” honeycomb filter.
2. Extended surface filters [Rigid Cells]: Deep Pleat, rigid cell extended surface filters, are the newer products. They are applied in many normal HVAC applications, previously reserved for the older V-banks. They are also used in clean room and microelectronic applications where contaminants are in the ppb or ppt [parts per trillion] range. These “Rigid Cells” utilize several different types of “thin bed” activated carbon media, that are formed into pleats that are 4″, 6″, or 12″ deep, the later being by far the most popular. The “deep” pleats are then sealed into a metal frame [rigid cell]. They can be used individually, but are normally used in a filter bank. Activated carbon loadings for a 24″ x 24″ x 12″ cell, vary from as high as approx. 7 lbs, to as low as slightly over 1 lb, depending upon the carbon filter media that is utilized.
3. V-Banks: They are used in airports, stadiums and commercial buildings and in many clean room applications. These products will offer from approx. 30 to 45 pounds of carbon per 1000 cfm of air, and are available for flow rates of 500, 1000 or 2000 cfm. Virtually all units will have a face area of either 24″ x 24″ or 12″ x 24″; utilize removable trays, V sections, or have a serpentine bed configuration; can be applied individually, or be built into filter banks.
Paint arrestors are engineered to trap liquid, solid, and waterborne paint droplets so they don’t build up in ducts and fans. Using a paint arrestor helps protect finish quality, keep the booth cleaner, and maintain compliance with environmental regulations.
Browse our paint filter products.
Standard HVAC filters are not designed to capture the sticky overspray found in spray booths. Using non‑paint filters can lead to poor finish quality, rapid clogging, unsafe paint buildup, and non‑compliance with air quality regulations.
Intake filters clean the air entering the booth so dust and dirt don’t land on the wet finish. They focus on fine particles and uniform airflow to reduce contamination.
Exhaust filters (paint arrestors) are designed to capture heavy paint overspray as the air exits. They focus on trapping liquid and waterborne paint droplets so they don’t build up. It helps protect finish quality, keeps the booth and exterior environment cleaner.
Replacement frequency depends on paint type, production volume, and booth airflow. They should be replaced whenever your finish quality or exhaust performance starts to degrade.
More efficient, higher‑capacity paint arrestors capture overspray more effectively and keep airflow stable, which leads to reduced wasted material and rework. In turn it creates a longer-lasting exhaust, supporting your product's utility and lifecycle.
Liquid paint overspray is often captured with fibrous or pocket-style paint arrestor media. Our filter that best handles this is the Series 107X Paint Arrestor Filter, manufactured by Viskon-Aire (a Rensa Filtration company).
Powder coating systems may use cartridge filters or specialized recovery systems designed to handle dry powder. The flagship option in our powder coating portfolio is the Series PM11 Powder Coating Cube Filter, a 3‑ply cube manufactured by Air Filtration Co. (a Rensa Filtration company)
A metal filter is a permanent, washable air filter constructed from metallic media. It captures larger particulate, mist, and grease. Metal filters can be repeatedly cleaned and reused instead of being discarded.
View our metal air filter selection.
In many commercial and industrial systems, a metal filter is used as a pre‑filter to protect coils and extend the life of higher‑efficiency final filters. A metal filter alone may be sufficient if fine particulate control is not critical.
Most metal filters are not designed as high‑MERV, fine particulate filters. They are best thought of as durable pre‑filters rather than MERV 11–16 “final filters.”
Rensa specializes in custom metal air filter housing and mesh configurations. Filters can be engineered to fit nonstandard sizes, materials, and MERV performance levels, ensuring compatibility with OEM systems or specialized industrial units.
View our metal filters selection.
The strength of a metal air filter lies in its structure. Rensa’s filters are built from layered sheets of expanded or woven metal mesh designed to capture airborne debris while preserving steady airflow. Each layer plays a role in maintaining filtration balance, reducing pressure drop, and supporting long-term mechanical integrity.
Common metallic media used in metal air filters are Aluminum, Galvanized Steel, and Stainless Steel.
Aluminum is lightweight, corrosion‑resistant, and easy to handle. It is a strong choice for most general HVAC and light industrial applications where temperatures are moderate and the environment is not highly corrosive.
Galvanized steel is a heavier and more rigid material. It has high mechanical strength and high temperature tolerance. It’s built for tougher industrial environments and rooftop units.
Stainless steel (304 or 430) is chosen for high‑temperature and more corrosive environments (oils, chemicals, washdown areas). 304 offers superior corrosion resistance; 430 is suitable where moderate corrosion resistance is acceptable and magnetic properties or cost are considerations.
As a general guideline, inspect the filter at least every 1-3 months. Clean the filter whenever you see visible loading on the media or when system pressure drop rises to your maintenance threshold. Avoid running the filter in an overloaded state. The key is maintaining consistent airflow—filters can be cleaned many times without losing performance.
Metal filters will maintain very consistent airflow and high performance over many wash cycles. Over time exposure to the elements can deform the mesh or frame, which can create bypass paths or slightly change resistance.
Inspect the filter after each cleaning for bent frames, broken mesh, or loose layers. If the media or frame is damaged, or if the filter no longer seats properly in the rack, it should be replaced.
Air filtration guidelines depend on your type of facility, because standards for a hospital, food plant, warehouse, office, cannabis grow, cleanroom, or manufacturing site follow very different requirements. The best first step would be to consult, learn what rules and frameworks apply to your building.
Contact a Rensa HVAC distributor in your area for an on-site filtration analysis, or research through our resources page to find your facility's requirements. As well, NAFA publishes best practices and guidelines for several facility applications, as well as current mandates and research provided by governmental and scientific communities. HVAC and air filtration professionals should use NAFA’s Best Practices and Guidelines as a tool to educate their clients on how to protect their facilities’ occupants.
A few of the main frameworks people usually follow are:
ASHRAE — HVAC and ventilation standards
CDC — infection-control recommendations
OSHA — worker exposure and ventilation requirements
EPA — indoor air quality guidance
ISO — cleanroom classifications
FDA — pharmaceutical and food-related environments
