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Commercial HVAC Filters | How Often to Change Them

In general, the majority of commercial HVAC filter manufacturers will advise replacing your air filter approximately every 90 days, or in other words, at a 3-month interval.


how often should you change commercial HVAC filters?

The frequency of changing a commercial HVAC filter depends on several factors, including the type of filter, the specific HVAC system, and the nature of the commercial space.


Join us on this journey to unlock the secrets of maximizing the performance of your HVAC system through strategic filter changes.


The Role of HVAC Filters

Commercial HVAC filters play a critical role in maintaining indoor air quality (IAQ) by acting as indispensable gatekeepers within the HVAC system.


Their primary function is to serve as a barrier against a spectrum of airborne particles and contaminants that, if left unchecked, could compromise both the air quality and the operational efficiency of the entire HVAC system.


1. Barrier Against Airborne Particles:

  • As air is drawn into the HVAC system, filters act as barriers that capture and trap various particles present in the air. These particles range from common dust and pet dander to more microscopic elements like allergens, bacteria, and even viruses.


2. Prevention of Airborne Contaminants:

  • By capturing and containing airborne contaminants, HVAC filters prevent these particles from being recirculated into the indoor environment.


3. Preservation of Indoor Air Quality:

  • The filtration process ensures the preservation of indoor air quality by removing pollutants and allergens.


4. Protection of HVAC Components:

  • Filters act as protective shields for critical HVAC components. By capturing particles before they can settle on components like coils, fans, and ductwork, filters contribute to the longevity and efficient operation of the entire HVAC system.


5. Enhancement of System Efficiency:

  • A clean and well-maintained filter contributes to the overall efficiency of the HVAC system. Unimpeded airflow allows the system to operate smoothly, reducing energy consumption and minimizing strain on components.


6. Contribution to Occupant Health:

  • Beyond mechanical considerations, the role of filters extends to promoting occupant health. By minimizing the presence of airborne contaminants, filters create a healthier indoor environment, reducing the risk of respiratory issues and allergies.


Types of Commercial HVAC Filters

Commercial HVAC systems employ various types of filters, each designed to address specific air quality needs.


Fiberglass Filters (standard):

  • Composition: Composed of layered fiberglass fibers.

  • Efficiency: Basic filtration for larger particles.

  • Suitability: Commonly used in residential and light commercial applications.

  • Advantages: Cost-effective and suitable for capturing larger particles.

  • Frequency: Every 1 to 3 months.

  • Considerations: Regular inspections are recommended, and filters should be changed more frequently if there are high levels of dust, allergens, or increased system usage.


Pleated Filters (standard):

  • Composition: Folded design with more surface area.

  • Efficiency: Higher efficiency in capturing smaller particles.

  • Suitability: Versatile and suitable for a range of commercial spaces.

  • Advantages: Greater surface area for improved efficiency, suitable for various commercial applications.

  • Frequency: Every 1 to 3 months.

  • Considerations: Regular inspections are recommended, and filters should be changed more frequently if there are high levels of dust, allergens, or increased system usage.


HEPA Filters (High-Efficiency Particulate Air):

  • Composition: Dense arrangement of fibers.

  • Efficiency: Exceptional at capturing very small particles.

  • Suitability: Critical environments like hospitals, laboratories, and cleanrooms.

  • Advantages: Highest efficiency in capturing particles, essential for environments with stringent air quality requirements.

  • Frequency: Every 6 to 12 months.

  • Considerations: High-efficiency particulate air (HEPA) filters are designed for superior particle capture. Their extended lifespan is balanced by the need for meticulous maintenance and monitoring.


Electrostatic Filters:

  • Composition: Charged fibers that attract particles.

  • Efficiency: Effective in capturing smaller particles.

  • Suitability: Often used in environments with specific air quality requirements.

  • Advantages: Captures smaller particles and can be reusable, reducing waste.

  • Frequency: For those with electrostatic or washable filters, it's advisable to give them a monthly spa day – wash, dry, and reinstall. The eco-friendly washable filters, when properly cleaned and reused, can proudly stand the test of time, lasting anywhere from 5 to 10 years.


Activated Carbon Filters:

  • Composition: Treated with activated carbon.

  • Efficiency: Effective in capturing odors and gases.

  • Suitability: Ideal for spaces where odor control is a priority, such as commercial kitchens.

  • Advantages: Effectively captures odors and gases, enhancing indoor air freshness.

  • Frequency: Every 3 to 6 months.

  • Considerations: These filters are effective in capturing odors and gases. Changes may be required sooner if there are significant odor issues.


UV (Ultraviolet Light):

  • Composition: Equipped with UV lamps.

  • Efficiency: Targets and neutralizes microbial contaminants.

  • Suitability: Used in conjunction with other filters to address microbial concerns.

  • Advantages: Targets microbial contaminants, contributing to enhanced hygiene.

  • Frequency: Annually.

  • Considerations: UV lamps need replacement annually to maintain their effectiveness in neutralizing microbial contaminants.


indicators for commercial HVAC filter replacement

Indicators for Commercial HVAC Filter Replacement

Regular monitoring of HVAC filters is crucial, and certain signs serve as indicators that a replacement is necessary. Being attentive to these signals ensures that the HVAC system continues to operate efficiently and maintains optimal indoor air quality.


Reduced Airflow:

  • Indicator: A noticeable decrease in airflow or weak ventilation.

  • Implications: Reduced airflow can strain the HVAC system, diminishing its ability to effectively distribute conditioned air throughout the space.


Increased Energy Consumption:

  • Indicator: A sudden spike in energy bills without a corresponding increase in system usage.

  • Implications: Clogged filters force the system to work harder, leading to higher energy consumption and increased operational costs.


Visible Dust on Vents:

  • Indicator: Accumulation of visible dust or debris around air vents.

  • Implications: Indicates that the filter is no longer effectively capturing airborne particles, allowing them to settle on surfaces.


Factors Influencing Filter Replacement Frequency


Occupancy Levels: 

Higher occupancy may lead to more rapid filter contamination.


Environmental Factors: 

Dusty or polluted environments may necessitate more frequent changes.


System Usage: 

Systems running seasonally will likely have less impact filter lifespan than an HVAC system that runs continuously.


Allergen Sensitivity: 

Spaces requiring superior air quality may prompt more frequent changes.


Importance of Regular Inspections:

  • Regular visual inspections can provide insights into the condition of the filter.

  • Utilize technology, such as smart air quality monitors or filter replacement alarms, for real-time data.


Monitoring Systems and Technologies

Advances in technology have introduced monitoring systems that provide real-time data on filter conditions, allowing for proactive maintenance and timely replacements.


Smart Air Quality Monitors:

  • Technology: Integration of smart sensors to monitor air quality.

  • Benefits: Real-time data on filter condition, allowing for timely replacements and efficient system operation.


Filter Replacement Alarms:

  • Technology: Alarms or notifications integrated into HVAC systems.

  • Benefits: Automated alerts when filters reach the end of their effective lifespan, prompting timely replacements.


It's essential to consult the HVAC system's manual for manufacturer recommendations and consider the unique demands of your commercial space.


Establishing a proactive maintenance schedule, monitoring filter conditions, and adapting the frequency based on specific factors contribute to sustained HVAC efficiency and optimal indoor air quality.


Understanding MERV Values


Explanation of MERV:

HVAC filters are distinguished by their Minimum Efficiency Reporting Value (MERV), a numerical rating that signifies their efficiency in capturing particles.


MERV values typically range from 1 to 20, with higher values indicating a higher level of filtration.


MERV values are determined through standardized testing (developed by ASHRAE) that measures a filter's ability to capture particles of varying sizes.


Filters with higher MERV ratings can trap smaller particles, offering enhanced filtration capabilities.


The scale is designed to help consumers and facility managers make informed decisions about the appropriate filter for their specific needs.


Commercial HVAC filter Minimum Efficiency Reporting Values (MERVS) chart
Source: www.epa.gov/indoor-air-quality-iaq/what-merv-rating

I. MERV 1-4: The Easygoing Crew

Filters in the MERV 1-4 range are the laid-back beach bums of filtration. They capture less than 20% of particles sized between 3.0 and 10.0 microns.


Think pollen, carpet fibers, and dust mites having a casual beach party. These filters are easy-breezy, allowing airflow to strut its stuff with minimal restriction and catching just a smidge of those particle vibes.


II. MERV 5-8: The Mid-Range Mavericks

Filters rocking a MERV score of 5-8 step up their game. They capture a decent chunk of particles sized between 2.5 and 5.0 microns, making them the mid-range mavericks.


These filters snag mold spores, pet dander, and fine dust particles. They're the workhorses, maintaining a balance between effective filtration and airflow.


III. MERV 9-12: The Heavy Hitters

Enter the heavy hitters – filters boasting a MERV value of 9-12. Capturing particles as small as 1.0 micron, they're the frontline defenders against finer particles.


Smoke, bacteria, and Legionella fall within their grasp. These filters are like the guardians of air purity, ensuring a higher level of cleanliness in the indoor environment.


IV. MERV 13-16: The Precision Guardians

Precision is the name of the game for filters in the MERV 13-16 range. As true guardians of air quality, they snatch particles as small as 0.3 microns.


This includes fine viruses, aerosols, and smoke. In spaces requiring meticulous control over air purity – hospitals, laboratories, or cleanrooms – these filters take center stage.


V. MERV 17-20: The Elite Protectors

At the pinnacle of the MERV scale are the elite protectors. With a rating of 17-20, these filters are on a mission to tackle ultra-fine particles under 0.3 microns.


They're the superheroes against viruses, bacteria, and microscopic allergens. Reserved for the most demanding environments, these filters provide unmatched protection and maintain pristine air quality.


Understanding MERV ratings empowers decision-makers to choose filters that align with specific air quality goals, ensuring a harmonious balance between filtration efficiency and system functionality.


  • Selecting Based on Filtration Needs: Choose a MERV rating based on the specific needs of the commercial space. For general purposes, a mid-range MERV rating may be sufficient, while specialized environments may benefit from higher-rated filters.


  • Balancing Filtration and Airflow: It's essential to strike a balance between filtration efficiency and airflow. Higher MERV-rated filters may necessitate more frequent replacements to prevent airflow restrictions.


  • System Compatibility: Consult HVAC system specifications to ensure compatibility with the selected MERV rating. Some systems may be designed to accommodate higher resistance filters, while others require a balance to maintain optimal performance.


  • Maintenance: Consider the maintenance requirements of each filter type, including replacement frequency and cleaning procedures.


dirty commercial HVAC filter

Consequences of Neglecting Filter Changes


Potential Damage to HVAC Systems:

Neglecting timely filter changes can lead to a cascade of issues that compromise the integrity and performance of the HVAC system.


System Overload:

  • Consequence: Clogged filters force the HVAC system to work harder to maintain airflow.

  • Result: Increased strain on components, potentially leading to overheating, system breakdowns, and costly repairs.


Reduced Efficiency:

  • Consequence: Restricted airflow due to dirty filters hampers the efficiency of the entire HVAC system.

  • Result: Reduced heating or cooling capacity, longer running times, and increased energy consumption.


Decline in IAQ:

Filters play a pivotal role in maintaining indoor air quality (IAQ), and neglecting their replacement compromises the air occupants breathe.


Airborne Particle Circulation:
  • Consequence: Clogged filters allow previously captured particles to re-enter the indoor environment.

  • Result: Elevated levels of dust, allergens, and pollutants in the air, leading to respiratory discomfort and potential health issues.


Microbial Growth:
  • Consequence: Dirty filters can become a breeding ground for bacteria and mold.

  • Result: Increased risk of respiratory infections and the circulation of unpleasant odors.


Impact on Energy Efficiency:

The energy efficiency of an HVAC system is closely linked to the condition of its filters, and neglecting replacements can have financial implications.


Higher Operational Costs:
  • Consequence: Reduced system efficiency leads to higher energy consumption.

  • Result: Increased operational costs and a negative impact on budget.


Equipment Wear and Tear:
  • Consequence: Overworked HVAC systems experience accelerated wear and tear.

  • Result: More frequent repairs and a shortened overall lifespan of HVAC equipment.


Recommended Action:

Recognizing the potential consequences of neglecting filter changes underscores the importance of adopting proactive maintenance strategies.


  • Regular Inspections

  • Scheduled Replacements

  • Professional Maintenance


Addressing the consequences of neglected filter changes requires a proactive approach to maintenance, ultimately preserving the reliability, efficiency, and air quality contributions of the HVAC system within commercial spaces.


Filter Change Procedures


Step-by-Step Guide:

Performing a filter change is a straightforward process, and a step-by-step guide ensures that the procedure is carried out efficiently and effectively.


Turn Off HVAC System:
  • Step: Begin by turning off the HVAC system.

  • Reason: This prevents the system from running during the filter change, ensuring safety and ease of access.


Locate the Filter Access Panel:
  • Step: Identify the filter access panel on the HVAC system.

  • Reason: Access panels vary, and locating the correct one allows for a seamless filter replacement process.


Remove the Old Filter:
  • Step: Carefully remove the old filter from its slot.

  • Reason: Removing the filter correctly prevents dislodging captured particles back into the system.


Check Filter Orientation:
  • Step: Ensure the new filter is oriented correctly, matching the airflow direction indicated on the filter frame.

  • Reason: Proper orientation optimizes filtration efficiency and system performance.


Insert the New Filter:
  • Step: Insert the new filter into the designated slot.

  • Reason: A secure fit prevents bypassing of unfiltered air and ensures optimal filtration.


Close the Access Panel:
  • Step: Close and secure the filter access panel.

  • Reason: A tightly sealed access panel maintains system integrity and prevents air leaks.


Turn On HVAC System:
  • Step: Turn the HVAC system back on.

  • Reason: Resuming system operation provides immediate benefits of enhanced airflow and improved air quality.


Following Manufacturer Recommendations:

Manufacturers provide specific guidelines for filter changes based on the type of filter used and system specifications.


Consult System Manual:
  • Action: Refer to the HVAC system manual for manufacturer recommendations.

  • Result: Following manufacturer guidelines ensures compliance with warranty requirements and optimal system performance.


Note Recommended Replacement Frequency:
  • Action: Take note of the recommended replacement frequency provided by the manufacturer.

  • Result: Adhering to the recommended schedule prevents issues associated with prolonged filter usage.


Conclusion

There is no one-size-fits-all solution when it comes to filter change frequency. Commercial spaces vary in size, usage patterns, and air quality goals.


Hence, a customized strategy that considers these factors is paramount.


Whether it's a routine DIY filter change or the engagement of HVAC professionals for comprehensive maintenance, the approach must align with the unique demands of each commercial environment.


Changing commercial HVAC filters is not merely a routine task; it's a strategic imperative.


It's a commitment to the optimal functioning of HVAC systems, an investment in energy efficiency, and a dedication to the health and comfort of those within commercial spaces.


If you enjoyed this article, stick around and check out others like it on the ETS blog!




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