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Furnace Filter vs. Air Purifier: Which Is Better?

Testing air filter

We all want to have clean air in our homes. That’s why many of us spend time researching the most efficient way to improve or maintain indoor air quality. While your HVAC system’s air filter is designed to improve whole-home air filtration, can adding a portable air filter help?

What Is the Purpose of an Air Filter? 

The name might be simple, but the task of cleaning your home’s air is quite complex. There are more than 50 sources of indoor air pollution that the standard air filter needs to remove from your home’s ventilation system before it sends the air back through your furnace vents. Some of those sources of indoor air pollution include:

  • Cleaning supplies
  • Mold
  • Smoke and particulate matter from cooking
  • Pet dander
  • Dust
  • Degrading building materials

How Effective Are Air Filters? 

The effectiveness of air filters depends on a wide range of factors, including how regularly they’re replaced and the efficiency of the heating system or air conditioner they work with. The most critical factor is the MERV rating of the air filter itself. The Minimum Efficiency Reporting Value of a filter indicates how well it removes debris from the air. Ranging from 1 to 20, air filters with the highest ratings can remove extremely small particles that lower rated filters miss. There is a drawback to high MERV ratings, however. A higher MERV score can also reduce airflow and make your HVAC system run more frequently, making it less energy efficient.

Here’s an example: A filter with a score of 14 removes 90% or more of particles three microns or greater and up to 75% of particles 0.3 to 1.0 microns. (A micron is .00003937 inches. Bacteria, for example, are roughly three microns long.)

How Effective Are Air Purifiers?

While your air filter must clean air from every room in your home, portable air purifiers are additional tools to remove irritants from specific rooms at a specific time. Some owners sleep with their air purifiers running, leave them on during the day, or keep them primarily in a living space in which they spend a lot of time.

Air purifiers are only effective at drawing in, purifying, and circulating limited amounts of air at a time. As far as efficiency goes, they utilize the same MERV scale as air filters. This simply means an air filter and an air purifier with a MERV rating of 14 will remove the same number of particulates.

What’s a HEPA Filter? 

HEPA filters are rated as the top three levels of filtration, or MERV ratings 17-20. Both air purifiers and HVAC systems can utilize this level of purification, but you may need to think twice. HEPA filters for a furnace can have drawbacks. Chiefly, they may restrict airflow to the point where it’s harder for warm or cool air to reach different rooms throughout the home. This may cause the HVAC system to run more often and need more frequent maintenance. And because these filters catch so much debris, they also need to be replaced much more often than standard air filters.

Who Wins, Air Filter vs Air Purifier?

In a sense, both are equally effective, though an air filter may be more cost-effective because it has a greater air cleaning capacity. For serious allergy sufferers, air purifiers offer additional purification power in rooms where they spend the most time. And with Americans spending roughly 90% of their time inside, air purifiers can’t hurt.

Replace Your Filter Regularly (And That Means All Your Filters!)

Whether you use just your HVAC’ system’s air filter or an air purifier, the biggest factor in maintaining excellent indoor air quality is to replace your filter regularly. In addition to changing your furnace filter at least every 90 days, stick to a regular maintenance schedule to keep your HVAC system operating smoothly.

Take a Deep Breath and Call Us 

How is your indoor air quality? From selecting the right air filter for your home and heating system to exploring opportunities to improve energy efficiency, One Hour Heating and Air Conditioning can help you breathe easily. Call (800) 893-3523 or request an appointment today.

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