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Dirty Air Filter

Air Filter vs. Air Purifier: What’s the Difference?

When it comes to maintaining a healthy indoor environment, understanding the difference between an air filter and an air purifier is essential. Many homeowners are familiar with the concept of filtering the air, especially through their HVAC systems, but not everyone is clear on how this differs from air purification. In this blog, we’ll dive into the differences between air filters and air purifiers, how they work, and how to choose the best option for your home.

What is an Air Filter?

An air filter is a device typically found in HVAC systems. Its primary function is to trap and remove particles from the air as it circulates through the heating, ventilation, and air conditioning system. Does the AC filter air? Absolutely. The filters in your AC unit are crucial for capturing dust, pollen, pet dander, and other common allergens, preventing these particles from recirculating through your home.

Most residential systems use mechanical filters, which capture particles on filter materials as air flows through. The effectiveness of an air filter is measured by its MERV rating (Minimum Efficiency Reporting Value), which indicates how well the filter can capture larger particles between 0.3 and 10 microns.

What is an Air Purifier?

Unlike air filters, air purifiers actively sanitize the air, which can include removing pollutants like gasses, odors, and even pathogens such as bacteria and viruses. Air purifiers work independently of your HVAC system, although some systems can be integrated. They utilize various technologies to clean the air, including HEPA filters, activated carbon, and UV light.

HEPA filters, used in many air purifiers, are highly effective at capturing particles as small as 0.3 microns. They can trap 99.97% of particulate matter, making them an excellent choice for homes needing a higher level of purification due to allergies or respiratory conditions. Activated carbon filters excel in removing odors and gases, while UV light purifiers use ultraviolet light to kill bacteria and viruses in the air.

Differences in Functionality

The key difference between an air filter and an air purifier is their approach to improving indoor air quality. Air filters mainly provide a passive filtering system that removes particles from the airflow. This is essential for maintaining clean air throughout a house but doesn’t eliminate all types of air pollutants, especially smaller particulate matter or gaseous pollutants.

On the other hand, air purifiers actively clean the air, addressing a broader range of contaminants, including those that can be hazardous to health, such as smoke, chemical vapors, and biological organisms. Does HVAC purify air? Standard HVAC systems equipped with basic air filters do not; however, with the integration of specific air purifying units, they can.

Choosing Between an Air Filter and an Air Purifier

Choosing between an air filter and an air purifier will depend largely on your specific needs:

  • Allergies and Asthma: If someone in your home suffers from allergies or asthma, a combination of high-quality air filters and purifiers can offer significant benefits. The air purifier’s ability to trap ultrafine particles can be particularly helpful.
  • Air Quality Concerns: If you live in an area with high pollution levels or if you have pets that shed dander and hair, combining both devices ensures cleaner indoor air.
  • Health Issues: For households with immune-compromised individuals, the sanitizing function of air purifiers may be necessary to minimize health risks.

Installation and Maintenance

Both air filters and air purifiers require regular maintenance to function effectively. For air filters, this means regular cleaning and replacement according to the manufacturer’s guidelines—typically every 90 days or so, depending on usage and the type of filter. Air purifiers might need more frequent attention, especially if they use multiple technologies such as HEPA filters and activated carbon.


Understanding the differences between an air filter and an air purifier can help you make informed decisions about how to best improve the air quality in your home. Whether you choose an air filter to block out common allergens or an air purifier to tackle a wider range of pollutants, both can significantly contribute to a healthier indoor environment.

For all your HVAC needs, including expert advice on integrating air purifiers with your existing system, don’t hesitate to call The Comfort Authority. Our team is dedicated to providing the best solutions for your home’s air quality. Trust us to help you breathe easier. Contact us today!