All About Air Filters: Types, Functions, and More




In the world of heating, ventilation, and air conditioning (HVAC), preventative maintenance stands as the cornerstone for system longevity and efficiency. Central to this maintenance regime are air filters–often understated yet vital components in the HVAC system. 

These filters not only purify the air we breathe but also safeguard the intricate machinery from dust and debris. Area Sheet Metal is here to highlight their importance, types, maintenance tips, and how they contribute to the overall health of your HVAC system.

Understanding Air Filters in HVAC Systems

Air filters serve a dual purpose in HVAC systems. Primarily, they trap and remove particles and contaminants such as dust, pollen, and bacteria from the air, contributing to a healthier indoor environment. 

But they also protect the internal components of the HVAC system from accumulating debris, which can impede performance and lead to costly repairs.

Before we go into the benefits of air filters, let’s discuss the different types of filters that you’ll find.

Types of Air Filters

Various types of air filters cater to different needs and system requirements:

Fiberglass Filters

Fiberglass filters represent the most basic and cost-effective option in the realm of air filtration for HVAC systems. Constructed from layered fiberglass fibers, these filters are designed to capture large particles of dust, lint, and other debris, providing fundamental air cleaning at an affordable price.

Advantages of Fiberglass Filters

  • Cost-Effectiveness: One of the most significant advantages of fiberglass filters is their affordability. They are an ideal choice for those on a tight budget.
  • Disposability: These filters are designed for single use, which means there’s no need for cleaning – simply replace them when they’re dirty.
  • Ease of Replacement: Due to their widespread availability and standard sizes, finding and installing replacement fiberglass filters is generally straightforward.

Limitations and Considerations

While fiberglass filters are suitable for basic protection, they have limitations:

  • Lower Filtration Efficiency: They are less effective at trapping smaller particles like pollen, mold spores, and pet dander compared to higher-end filters.
  • Frequent Replacement Needed: Because of their simpler construction, they tend to clog more quickly and require more frequent replacement – usually every 30 to 90 days.
  • Not Ideal for Allergy Sufferers: For households with allergy sufferers, pets, or higher air quality needs, a more advanced filtration solution might be necessary.

Pleated Filters

Pleated air filters offer a significant step up in air filtration quality compared to basic fiberglass filters. These filters are crafted from higher-quality materials, typically polyester or cotton folds, which are pleated or folded to increase the surface area for trapping pollutants.

Superior Filtration Efficiency

  • Enhanced Particle Capture: The pleated design effectively captures a wide range of particles, including dust mites, pollen, mold spores, and pet dander. This makes them particularly beneficial for households with allergy sufferers or pets.
  • Higher MERV Ratings: Pleated filters generally have higher Minimum Efficiency Reporting Values (MERV), indicating superior filtration capabilities compared to basic fiberglass filters.

Increased Durability and Lifespan

  • Robust Construction: The materials used in pleated filters are more durable, allowing them to withstand normal wear and tear better and maintain efficiency over time.
  • Longer Replacement Intervals: Due to their enhanced durability and filtration capacity, pleated filters do not require as frequent replacements as fiberglass filters. They typically last from 3 to 6 months, depending on usage and environmental factors.

Energy Efficiency and Airflow

  • Improved Airflow: The pleated design allows for greater surface area without compromising airflow through the HVAC system. This can contribute to better system efficiency and lower energy costs.
  • Preventing HVAC Strain: By effectively capturing more particles and maintaining good airflow, these filters help prevent strain and potential damage to HVAC systems.

Considerations for Use

  • Slightly Higher Cost: Pleated filters are more expensive upfront than fiberglass filters. However, their longer lifespan and superior filtration can provide better value in the long run.
  • Size and Compatibility: It’s important to choose the right size and thickness to ensure compatibility with your HVAC system. Some systems may require specific types of pleated filters to operate efficiently.



HEPA Filters

High-Efficiency Particulate Air (HEPA) filters represent the pinnacle of air filtration technology in the HVAC industry. They are specially designed to capture a remarkably high percentage of airborne particles, even those as small as 0.3 microns in diameter, which is much smaller than what can be captured by standard pleated or fiberglass filters.

Exceptional Filtration Capabilities

  • Capturing Ultrafine Particles: HEPA filters excel in trapping very fine particles, including pollen, dust mites, tobacco smoke, and bacteria, offering superior air purification.
  • High MERV Ratings: These filters typically have the highest MERV ratings, indicating their exceptional ability to filter out the smallest particles from the air.

Benefits for Health and Air Quality

  • Ideal for Allergy and Asthma Sufferers: Their superior filtration capabilities make HEPA filters an excellent choice for households with individuals suffering from allergies, asthma, or other respiratory issues.
  • Reducing Airborne Contaminants: HEPA filters effectively reduce the concentration of harmful airborne particles, contributing to a healthier indoor environment.

Considerations for HVAC Systems

  • Compatibility and Installation: It’s crucial to ensure that your HVAC system is compatible with HEPA filters. Some systems may require modifications to accommodate these high-density filters without compromising airflow or efficiency.
  • Potential for Increased Load on HVAC: Due to their dense filtration material, HEPA filters can restrict airflow more than other types of filters, potentially placing an additional load on the HVAC system. Proper installation and regular maintenance are key to preventing system strain.

Importance of Regular Filter Maintenance

Are you properly maintaining your furnace filters? Learn the reasons why it’s important to keep your filters in working order.

Enhancing Air Quality

Regularly changing or cleaning air filters ensures a consistent flow of clean, healthy air. This is especially important in environments sensitive to dust and allergens, like homes with pets or individuals with allergies.

Preventing HVAC System Strain

A dirty or clogged filter forces the HVAC system to work harder, increasing energy consumption and the risk of mechanical failure. Timely filter maintenance keeps the system running smoothly and efficiently.

Best Practices for Air Filter Maintenance

Are you wondering how to maintain your furnace filters? Consider these tips from Area Sheet Metal Heating + Cooling:

Regular Checks and Replacement

It’s essential to regularly check air filters and replace them as needed. The frequency can vary depending on the type of filter, usage, and environmental factors.

Keep in mind that if you are part of our Discount Club, we can take care of maintenance checks for you!

Choosing the Right Filter

Selecting the appropriate filter for your system is a must. Factors to consider include the size of the filter, the specific needs of the household (e.g., allergy concerns), and the recommendations of the HVAC system manufacturer.

Get Help with Preventative Maintenance from Area Sheet Metal

Investing time and effort in understanding and maintaining air filters is a small yet impactful step in the broader context of HVAC system care. 

Regular maintenance of air filters not only ensures a healthier living environment but also safeguards the HVAC system, enhancing its efficiency and lifespan. With the help of our preventative maintenance, you can enjoy uninterrupted comfort and optimal air quality in your space. Ask us about joining our Discount Club!