HEPA Filter for Your Furnace
Most end users of filters, whether they are purchasing filters for their home or for a commercial or industrial application, do not know much about them. However, what people have heard of is HEPA filters. It’s a short, catchy acronym, and people know it means they’re getting a good filter.
Well, unfortunately, a “good” filter isn’t so cut and dry. It’s very situational. Unless your application is one of a few specific uses, such as in a hospital, pharmaceutical production or laboratory, you probably don’t need a HEPA filter.
Choking Your Furnace
People don’t always consider this, but the filter used in any system will reduce the pressure of air moving through that system. This is known as pressure drop. (explanation of pressure drop, please read this post.) Most systems are designed with a certain amount of pressure drop from filters in mind, and while they can handle some variation, the difference between a standard pleated filter, like our MERV-8 Taff Pleat and a HEPA filter is significant.
To give an example, the filter I use in my home furnace is a 16”x25”x1” Taff Pleat MERV 8, High Capacity. It has an initial pressure drop of 0.13”WC, at 500FPM of air speed.
If I were to modify my furnace so it could accept a 24”x24”x2¾“ Micropleat HEPA filter, one of the Parker filters we are proud to distribute, I would immediately experience a serious reduction in air pressure, since this filter is rated for an initial resistance of 0.45”WC, at a mere 90FPM of air speed. My fan would be overworked, trying to push through the air required to heat my home.
Multi-Stage Systems
Most HEPA filters are designed to be the final filter in a two or more-stage filtration system. In a multi-stage system, less efficient filters, or pre-filters, are used to remove larger particles from the air, leaving only the smallest particles for the final, most efficient, and most expensive fitler to remove. Without the pre-filters, large particles will clog the HEPA filter quickly, drastically shortening the service life. If your system is not set up for pre-filters, you would run into this issue.
Not A Significant Help Against Infections
It is currently March 10, 2020, and COVID-19, is dominating the headlines. It might seem like a wise move to install a HEPA filter to protect your home, office or factory from the spread of COVID-19, or similar viruses.
The Government of Canada has released an FAQ on COVID-19. According to this article, these are the ways COVID-19 spreads:
respiratory droplets that are spread when you cough or sneeze
close personal contact, such as touching or shaking hands
touching something with the virus on it, then touching your mouth, nose or eyes before washing your hands
Please note: None of these factors will be eliminated by the installation of a HEPA filter.
The article goes on to list ways to protect oneself from COVID-19:
washing your hands often with soap and water for at least 20 seconds
avoiding touching your eyes, nose or mouth with unwashed hands;
avoiding close contact with people who are sick;
coughing or sneezing into your sleeve and not your hands; and
staying home if you are sick to avoid spreading illness to others.
Once again, a HEPA filter will not assist with any of these preventative measures.
Consider a Pleated Filter
Pleated filters, the most common filter in the HVAC market, are available in efficiencies ranging from MERV 8 to MERV 13. For most applications, a MERV 8 Pleated filter does everything you need. For certain applications, such as when regulation requires a higher efficiency, or meeting LEED standards; or for dealing with allergies and asthma, MERV 11 and MERV 13 filters are appropriate.
Please feel free to contact us for any questions or concerns.
Written by: Michael Lopez