You may not realize it, but air pollution is an even bigger problem indoors than out. The quality of the air in your home is many times worse than the outdoor air, with mold, dust, pet dander and other pollutants accumulating over time. Some of these contaminants can be eliminated simply by running your HVAC system. As the air cycles through your home, it runs past an air filter, which captures and eliminates particles in the air. However, your HVAC air filter can only do so much. If you really want to improve indoor air quality, consider HEPA filtration.
HEPA stands for high efficiency particulate air, and this type of filtration is designed to function at a significantly higher level than a standard air filter, removing 99.97 percent of all particles in the air, down to 0.3 microns or smaller. This includes everything from dust and mold to viruses and bacteria to cigarette smoke, and more.
HEPA filters are rated between 17 and 20 on the minimum efficiency reporting value (MERV) scale. MERV ratings measure the minimum size of particles that the filter is able to capture and eliminate from the air. Since the smaller the particle, the more dangerous is it is to inhale, the highest rated filters are the ones that can remove the smallest particles.
Here’s a basic breakdown of MERV ratings and what they mean:
- MERV 1-4 – The lowest rated air filters, they can only remove larger particles, such as pollen, dust mites or carpet fibers.
- MERV 5-8 – Filters with this rating are able to remove mold, dust and pet dander, and are designed for whole-house HVAC systems in residences.
- MERV 9-12 – Providing superior residential filtration, it can remove things like milled flour and car emissions.
- MERV 13-16 – These filters are generally used in hospitals and can remove bacteria, sneeze droplets and more.
- MERV 17-20 – These HEPA filters are designed for laboratory clean rooms and the like.
Since HEPA filtration is designed for such thorough air cleaning, it’s different from your standard HVAC filter. Your HVAC system can take filters with MERV ratings of up to 12 at most. But higher rated filters, such as HEPA, are much thicker and heavier, and as such, they’ll restrict airflow through your system, wasting energy and ultimately damaging it.
To use HEPA filtration, you need a special, separate air filtration system for your home that produces enough air pressure to accommodate the thicker, higher rated filters. These systems generally take air out of the regular airflow through your HVAC system, run it through the filter, and then integrate the cleaner air back into the airflow, as it’s distributed to your home.
As previously mentioned, a HEPA filter is required to remove a minimum of 99.97 percent of particles from the air. This means that the first time the air passes through the filter, it removes almost all the contaminants. The second time it cycles through, it removes 99.97 percent of the remaining contaminants, and so on. The result is that your home’s air will be virtually entirely free of all harmful particles.
What Is HEPA Filtration Good For?
It’s ideal for the homes of people with allergies, asthma or other afflictions that require them to be more particular about air contaminants. But air filtration is only one way of maintaining good indoor air quality. It also helps to vacuum regularly, keep your house clean, and keep windows open to let in fresh outdoor air. Still, it’s essential to keep your HEPA filtration system functioning at peak performance, so you can continue to enjoy clean air. This means replacing the filter.
A regular HVAC filter should be replaced every one to three months. A HEPA filter is designed to last much longer, generally one to two years. While it can be convenient not to have to worry about changing the air filter as often, it can also make it easier to forget. But it’s essential that the air filter is changed regularly, particularly with higher rated filters. If you allow it to get clogged, the contaminants will restrict airflow, wasting energy and damaging the system.
In addition, when the filter can’t hold any more particles, contaminants can end up being circulated back into the air, completely defeating the purpose of having HEPA filtration. For clean, contaminant-free air, be sure to change both your HVAC filter and your HEPA filter at the proper intervals.
For more advice on HEPA filtration and ensuring clean air in your home, contact us at Griffith Energy Services, Inc.
Written by Kevin Spain.
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