The Nitty-Gritty of Good and Bad HVAC Filtration

with John Ellis

How confident are you that your HVAC filter is actually keeping your home’s air clean? Indoor air quality expert John Ellis reveals the difference between effective and ineffective filtration and explains why the wrong filter can leave you with a dusty home, wasted money, and potential health risks. John breaks down how filtration works, what MERV ratings mean, and the hidden trade-offs that manufacturers often don’t explain. You’ll discover why some filters fail, how to avoid common mistakes, and why particulate size matters. Walk away confident in your ability to select, size, and maintain the right filter to protect your HVAC system, your home, and your family’s health.

In this mini class, you’ll learn:

  • Six key principles to address indoor air quality. Air filtration and its history (4:14)

  • The pros and cons of filters and expectations about them. Why duct cleaning should not be necessary. (12:18)

  • Types of filters and most common filtration effects. (18:23)

  • Adsorption and activated carbon. How activated carbon is made and what it can filter. (25:44)

  • How many filtration effects are used, what filters are designed to do, and how filters are rated. (35:00)

  • How to tell if your filter is large enough, along with an illustration. (38:56)

  • Catastrophic failures due to poor air flow. Designing a system for your static pressure budget, MERV ratings, and the impact of filters. (45:03)

  • The purpose of ASHRAE 52.2. The importance of particulate size and how particulates affect human health. (51:52)

  • How filters are designed and computational fluid dynamics. (57:00)

  • Dust Free’s filtration system. (1:03:36)

  • Whether a filter can capture particles smaller than 0.3 microns. (1:07:15)


Download the transcript here.

Watch More Episodes From Our HVAC + D Mini Class Series here:
https://changetheairfoundation.org/understanding-hvac-d/

Thank You To Our Sponsor!
Santa Fe Dehumidifiers: www.santa-fe-products.com

Links Mentioned in This Interview:

Understanding Air Cleaners & Purifiers with Carl Grimes: https://changetheairfoundation.org/understanding-air-cleaners-purifiers-with-carl-grimes/

Get In Touch With Our Guest:
John Ellis’ Phone Number: 505-652-8119

Learn More About Change The Air Foundation:
https://www.changetheairfoundation.org

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