Not all air filters are created equal. Some air filters have wildly diverging particle capture efficiency from other filters. A “bad” air filter, or low-quality air filter, is less effective in capturing smaller particles and can bow and restrict airflow, reducing performance and forcing your HVAC system to work harder. This can lead to higher energy bills and lower efficiency, and in some cases, the air filter can get sucked into the system and cause significant damage. Investing in a quality air filter may cost more initially, but it will ultimately provide better indoor air quality and equipment protection. This article will explain the benefits of using high-quality air filters.
When selecting an HVAC air filter, choosing one that meets your specific needs is essential. For example, you may want to decrease virus transmission in a school or workplace. In this case, it’s best to use a MERV 13-A filter in the air handling unit of the HVAC system and couple it with a portable HEPA air cleaner to maximize particle capture efficiency.
What are the main differences between a cheap air filter and a high-quality air filter?
- A poor HVAC air filter fails to meet MERV standards and is ineffective in filtering out particulate matter
- This type of filter may get clogged too often, reducing its effectiveness and even harming your HVAC system over time
- In the worst-case scenario, a bad filter could even allow pollutants and other harmful particles to enter the air in your building, negatively affecting your health and well-being
- Therefore, it is crucial to choose a high-quality HVAC air filter that meets the necessary ASHRAE (American Society of Heating, Refrigerating, and Air-Conditioning Engineers) standards to ensure that you breathe clean, healthy air
- High-quality air filters capture more allergens, reduce risks of cardiovascular problems, and reduce asthma
- High-quality air filters protect HVAC systems from dust and contaminants, extending their lifespan and preventing costly repairs
- Cheaper filters require more frequent replacement and may cost more than high-quality air filters in the long run
- Investing in high-quality filters can be a cost-effective long-term solution, as they last longer and require less frequent replacement, reducing the need for costly replacements
The type of media used in an air filtration system is crucial for its performance
Here are some reasons why:
The air filter’s media, including particle removal efficiency, dirt holding capacity, material quality, media variety, and application specificity, all play a crucial role in its longevity and performance. Unobstructed exposure to airflow increases air passage, lowers pressure drop, and provides more media area for particle removal. The type of media influences dirt-holding capacity, affecting filter longevity.
An HVAC air filter’s frame construction and material are crucial for stability, proper fitting, holding capacity, and protection. Reinforced frame construction ensures stability. Filter-holding frames provide rigidity and durability for built-up HVAC applications.
Accuracy is crucial when measuring MERV ratings because some filters can degrade over time. It’s similar to car gas mileage ratings. Fuel efficiency ratings for cars are based on optimal conditions, flat roads, ideal weather, and a new engine. Your vehicle will not match the rated performance in many real-world conditions. However, these ratings are a standard used to compare vehicles to each other across brands and models and give you an expectation of results over the vehicle’s life. For air filters, you want a product that maintains its efficiency and reliability over time. Therefore, it is essential to establish and follow industry standards that can test and prove the filter’s efficiency under all conditions, ensuring that it will maintain its performance after purchase.
The most important thing about high-quality, high-efficiency filters is that they remove more tiny particles that are the most harmful to human health.
In terms of particle capture efficiency, a MERV 13 filter is more effective than a MERV 10 filter in capturing particles across all channels. However, the significant difference is that MERV 13 filters have a test report demonstrating their ability to capture fine particles to qualify as MERV 13 filters. On the other hand, achieving a MERV 10 rating without any efficiency in capturing fine particles is possible, as MERV 10 filters are only tested for their ability to capture larger particles.
Suppose you are looking to protect your building from harmful particles. In that case, it is generally recommended to use a MERV 13/13-A filter as they are more effective in capturing particles that can cause harm to humans.
If you look at the chart, achieving a MERV 10 rating is possible despite having low particle capture efficiency on fine particles. MERV 13/13-A is the preferred choice to catch even the smallest particles that could harm humans. MERV 13 pleated filters are suitable for home units. However, this efficiency in 1″, 2″, and 4″ pleated filters usually utilizes an electrostatically enhanced filter, which will decrease in efficiency over time. It is unknown when this decrease will begin as it depends on run-time, particle load, and velocity, so it is recommended to change these on a 3-month maximum schedule to try and avoid decreased efficiency.
Camfil Canada air filtration expert Berni Baier states, “I would like to highlight that a MERV 13 filter has a test report which shows the percentage of fine particles it can capture. On the other hand, a MERV 10 filter can achieve its rating without capturing fine particles, as it only tests for larger particle capture efficiency. Therefore, when choosing an air filter, you must consider what you want to protect against. MERV 13 filters are becoming more popular because they capture more particles that can harm humans.”
Some products available in retail stores or online use their own efficiency rating. ASHRAE standards, or any other standards, are not followed, and there is no real accountability regarding the ratings. It is crucial to ensure that the filter you purchase has a MERV rating value and has been tested under MERV testing criteria.
Do cheaper air filters get clogged faster or obstruct airflow?
Yes, cheaper air filters get clogged faster and obstruct airflow sooner than high-quality air filters. If the pleats on a filter are bunched together, less media is available for particle capture. This also means that the air movement is decreased because the air has difficulty going through the media due to a lack of proper open-area media. When looking at a high-quality air filter, you should be able to see all the media across that filter and that no pleats are blocked.
Can a clogged home or office air filter lead to higher energy bills?
Yes, the HVAC system works harder when the air filter gets clogged. Most homes don’t have Variable Frequency Drive (VFD) systems like offices, commercial or industrial buildings. On a VFD system, you can adjust the fan speed to regulate the amount of air, which will save energy, but on constant speed systems in homes and in older buildings, you cannot. There is an indirect effect on your energy bills. As the filter gets clogged up, less air enters the building, which means the furnace and air conditioner will cycle more often, using more energy. Air filters that can handle more dust loading capacity are always better than those that cannot because there is less energy consumption and higher particle capture efficiency, which affects the health of building occupants. Lastly, high-quality air filters protect heating and cooling coils.
On a VFD-controlled fan, you can measure the energy used, making it easier to regulate the HVAC system. In all applications, having a clogged filter will cost you more directly or indirectly in energy use. A clogged filter can also shorten the life of your HVAC system.
Can a clogged home or office air filter lead to higher energy bills?
Yes, the HVAC system works harder when the air filter gets clogged. Most homes don’t have Variable Frequency Drive (VFD) systems like offices, commercial or industrial buildings. On a VFD system, you can adjust the fan speed to regulate the amount of air, which will save energy, but on constant speed systems in homes and in older buildings, you cannot. There is an indirect effect on your energy bills. As the filter gets clogged up, less air enters the building, which means the furnace and air conditioner will cycle more often, using more energy. Air filters that can handle more dust loading capacity are always better than those that cannot because there is less energy consumption and higher particle capture efficiency, which affects the health of building occupants. Lastly, high-quality air filters protect heating and cooling coils.
On a VFD-controlled fan, you can measure the energy used, making it easier to regulate the HVAC system. In all applications, having a clogged filter will cost you more directly or indirectly in energy use. A clogged filter can also shorten the life of your HVAC system.
High-quality air filters and pressure drop
Higher-quality filters may require fewer changes but could start at a higher pressure drop. It’s essential to strike a balance between quality and pressure drop. For instance, a Camfil air filter typically has a higher initial pressure drop than its competitors but a much lower average pressure drop over its life. A competitor’s filter could start at 0.25 in. w.g. when new, be at 0.31″ w.g. at 3 months, and 0.45″ w.g. at 6 months of use. A Camfil 30/30 filter starts at 0.31″ w.g. new, 0.31″ w.g. at 3 months, and +0.35″ w.g. at 6 months.
What’s the best way to ensure good indoor air quality in your home, office, or school HVAC systems?
The best way to improve the air quality in your home or building while using a certified MERV filter involves 3 steps you can take in sequence:
1. INFILTRATION REDUCTION: Pressurize the indoor environment so contaminants cannot come in. This can be done by using residential or commercial heat exchangers with proper filtration to bring in conditioned outside air
2. GENERATION REDUCTION: Remove any items indoors that can generate particles/VOCs (carpets, air fresheners, VOC-generating photocopiers, etc.)
3. CIRCULATION: Keep your system running as much as possible and let the fan move more air through your building while utilizing proper air filters. Use portable air cleaners in areas where you spend the most time
These steps can be applied to any space. It’s essential to follow the sequence as each step affects the effectiveness of the others. If you can’t stop the infiltration or generation of particles, your filter and air handler won’t be able to provide clean air. By following these steps, your building will have optimum air quality. As discussed earlier, high-quality filters like the 30/30® Dual 9 filter last longer than cheaper alternatives despite requiring a more significant initial investment. You can save more money in the long run without worrying about replacing filters as often. For instance, the 30/30 filter can last anywhere from 6 to 9 months in a standard home, and if you don’t have high particle generation (pets, construction/renovation, etc.), it’s possible to use a one-inch filter for a year. A Dual 9 filter can last a year or more.
Save money and time by buying a longer-lasting air filter
Manufacturers typically recommend changing air filters every three months, as this is the safest option for the filter and ensures more sales. Baier advises that in residential applications where furnaces cannot handle much pressure drop, you first need to decide which is the main priority: long life or higher efficiency. If you want longer filter life, install a well-constructed MERV 8/8A or MERV 9/9A filter, such as a 30/30 or 30/30 Dual 9, that lasts from 6 months to over a year. If you want high efficiency, install a MERV 13 pleated filter, and because it is electrostatically enhanced, change it every 3 months to avoid the point where it begins to decrease its efficiency. You can extend filter life in both scenarios by installing a thicker filter with minor retrofitting (e.g., changing from a one-inch-thick filter to a four-inch-thick filter). Commercial/Industrial units should use well-designed MERV 13/13-A or higher efficiency filters to maintain efficiency and long life.
Using longer-lasting filters, such as a MERV 30/30 Dual 9 prefilter in an office application, can decrease maintenance costs. Four change-outs of a competitor’s $4 filter costs $16/yr, vs one change-out of a Camfil Dual 9 $14 filter which costs $14/yr. This represents a $2/opening product cost savings, as well as a labour cost reduction and waste reduction.
How can you choose the right air filter for commercial purposes?
For most offices, a two-stage filtration process is necessary for better air quality. The first stage is a prefilter that cleans the air before it reaches the final filter. A high-quality prefilter is relatively inexpensive and can last 9 months to a year. Final filters are more expensive and require a minimum MERV 13 rating. They can last up to 5 years. This setup can save you a lot of money over time because there is less labour involved in the change-outs, and you can reduce the number of filters purchased. Read more on the total cost of ownership (TCO)
For office buildings with a central unit, the HiFloES® is a good solution. It’s a single-stage solution available in MERV 11, 13, 14 and MERV 15; all models are also MERV-A. They have 12″, 15″, 22″, and 30″ pocket depths. The HiFloES doesn’t require a prefilter and is guaranteed for a year.
Retrofitting a rooftop unit may be complicated due to space constraints. But for a walk-in air handling unit system, changing the tracks or frame is straightforward. If it’s a front-load filter bank, you usually only need to change the clips.
What does a BAS (Building Automation System) do?
BAS systems are primarily designed to save energy rather than improve filtration efficiency. BAS systems allow you to control devices like VFDs and air handling units remotely. However, BAS systems don’t measure the efficiency of air filters. To measure air quality, you need a separate portable indoor air quality monitoring system that can be connected to your BAS system. With an indoor air quality monitoring system, you can monitor the air quality within the building and take steps to improve the airflow and decrease particle levels. While some companies have started to switch to this system, it has yet to be widely adopted.
Is it a good idea to buy an air filter with an antimicrobial coating on the media?
It’s important to understand that antimicrobials only work on particles that adhere to the filter’s fibres. They do not neutralize particles that pass through the filter. Particles have to make contact with the chemical to be neutralized. Suppose a filter stops 50% of the particles, and one million particles pass through the filter. In that case, 500,000 particles will pass through the filter unaffected by the antimicrobial coating, provided they do not touch the fibre. Also, it’s essential to consider that antimicrobial treatments may have toxic effects on people or cause adverse effects by releasing volatile organic compounds (VOCs).
Baier says, “We do not promote antimicrobial coatings. Our philosophy is to collect as many particles as possible so they do not pass through the filter. Currently, we do not know of any good antimicrobial coating processes. Mechanical filtration is the best option right now. Antimicrobial coatings can be used on mechanical or electrostatic filters, but particle neutralization efficiency is poor.”
Are washable air filters more sustainable?
Electronic Air Cleaners can initially have high efficiency, but as they collect contaminants, their efficiency decreases. When you wash them, contaminants are always left on the filter, decreasing efficiency. So, washable electrostatic filters decrease in efficiency over time. The argument that washable filters are more sustainable is not entirely valid. Mechanical filters with the highest energy efficiency rating are the best choice for sustainability. Also, with MERV-A-rated mechanical filters, you’ll always know their particle capture efficiency, as they must be tested under ASHRAE Appendix J. For instance, if you put in a MERV 8-A filter, it will be a MERV 8-A filter from the beginning to the end of its life. A washable, electrostatic filter cannot perform as well as a mechanical filter.
How to be more sustainable with your air filter purchases
Suppose you want to be more sustainable, using longer-lasting filters to reduce the number of filter changes and minimize waste. It’s important to use air filters with the correct Minimum Efficiency Reporting Value (MERV) rating that meets your needs. Using filters with a lower MERV rating than required, for example, using a rating of MERV 1 or 2 when you need MERV 8 or 10, is insufficient. The primary purpose of a filter is to capture particles, so if it’s not doing its job, it’s as good as not having a filter at all. Therefore, it’s best to determine the appropriate efficiency of the filter you want to buy and then consider its environmental impact.
Air filter quality standards
The ISO (International Organization for Standardization) has established a globally recognized test standard, ISO 16890. It classifies filters based on their ability to capture various particle sizes. www.iso.org/standard/57864.html
Particulate matter refers to tiny particles that can be harmful to human health:
- PM1 (0.3-1.0 µm)
- PM2.5 (0.3-2.5 µm)
- PM10 (0.3-10 µm)
Another standard of efficiency for air filters is the MERV rating. MERV ratings are classified from MERV-1 to MERV-16. A MERV-1 filter can only capture less than 20% of particles in the 3 -10 µm range and 0% of particles from 0.3 -3.0 µm. On the other hand, a MERV-16 filter can remove more than 95% of particles from 0.3 to 10 µm. This is important because the particles most harmful to human health are in the PM1 and PM2.5 range. PM1 – particles are less than 1 μm in size. For example, dust, combustion particles, bacteria, and viruses. PM2.5 – particles are less than 2.5 μm in size—examples: pollen, spoors and other organic particles.
This classification system allows users to accurately assess levels of particulate matter that will pass through filters at each MERV level and match it to their individual needs. Filters not meeting this requirement may lead to poor air quality, compromising performance.
To filter out PM10, PM2.5, and PM1 particulate matter- a filter must effectively separate at least 50% of the particle fraction for that class. Otherwise, it is categorized as a coarse filter which cannot capture fine particles.
For example, a MERV 13 air filter can capture 90% of particles as small as 1 micron, leading to a healthier indoor environment. By contrast, cheaper air filters with lower MERV ratings may only be able to capture larger particles-particles that may already be filtered out by our body mechanisms- leaving smaller and more harmful particles to circulate. Investing in high-quality air filters reduces the risk of respiratory issues and protects your filtration system, leading to better overall system performance, less maintenance, and better energy efficiency.
Camfil Products:
Durafil ES
AP13SC
AQ13
https://www.camfil.com/en-ca/products/general-ventilation-filters/panel-filters/aq/aq13-_-68953
Durafil
Hi-Flo ES
About Camfil Canada Clean Air Solutions
For more than 60 years, Camfil has been helping people breathe cleaner air. As a leading manufacturer of premium clean air solutions, we provide commercial and industrial systems for air filtration and air pollution control that improve worker and equipment productivity, minimize energy use, and benefit human health and the environment. Read more about Camfil Canada
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Sources:
American Society of Heating, Refrigerating, and
Air-Conditioning Engineers. (ASHRAE)
Media Contact:
Phillip Ilijevski
Camfil Canada Inc.
T: 437-929-1161