How Do Furnace HEPA Filters Work?
Nobody wants to breathe in dirty and dusty air, so it’s important to make sure that your home has adequate filtration to keep airborne particles under control. Furnace filters work hard to capture and contain the majority of household dirt and dust and keep it out of the air you breathe, but to get ‘extra clean’ air you may need to invest in a HEPA filter. How do these filters work, and are they really worth the money? Let’s talk about it!
Ever see a bright beam of sunlight streaming in through a window in your home, only to have it show all kinds of little particles and fibers floating around in the air? It’s easy to forget that these tiny particles are hanging around in your house, getting stirred up into the air as the family moves around and goes about daily routines. To help keep dust to a minimum in your home, recirculating the air through the furnace filter will capture many of these pesky particles and get them out of your air.
Changing the filter regularly with a good quality, high-efficiency replacement furnace filter helps to make sure that your furnace is always operating at peak performance. However, sometimes there are situations where something more powerful is needed to really clean and scrub the air in your home. Situations like this are where a HEPA filter comes in very handy.
What Does the Acronym in HEPA Filter Stand For?
The acronym stands for ‘high-efficiency particulate air’ filter, and is a term that is only applied to air filters that are capable of capturing and retaining airborne particles that are 0.3 microns in size with an astounding 99.97% efficiency rating. How small is 0.3 microns? Pretty darn small, actually! Compare that to a typical pollen or dust particle, which comes in between 10-100 microns in size, or a human hair strand that’s 50 microns wide, and you can get some idea on just how incredibly effective HEPA filters are at cleaning the air.
For context, a regular stock furnace filter with a MERV rating of 8 is about 85% efficient in capturing airborne particles between 3 and 10 microns. A higher-quality furnace filter with a MERV rating of 12 increases this capture efficiency up to about 90%. HEPA filters are able to capture particles 10x SMALLER at 0.3 microns, and do so with a far higher efficiency rating.
How Do HEPA Filters Work?
Filters in general work by passing air through a permeable material where the small particles floating in the airstream contact the material and become trapped. Most home furnace air filters are made from materials such as fiberglass, polyester fabric, cotton fabric, or blends of multiple materials. The tighter the weave of the fibers in the filter material, the smaller the particles they are able to capture. HEPA filters take this concept and build on it by employing a sequential series of layers of filter material that progressively capture more and more airborne particles as the air moves through each layer.
As the air moves throughout the HEPA filter, particles become trapped as they directly impact the filter material and become embedded in it, or are attracted to the material by a static electric charge where they become stuck. In addition, because the particles in the air must pass through so many layers of filter material, their speed gradually decreases with each progressive layer. Even if particles do not directly impact or become attracted to the filter fibers within the first few layers, they will eventually become trapped by the subsequent layers before they can re-enter the surrounding air.
What Are The Benefits of HEPA Filtration In The Home?
There are numerous benefits to having a HEPA air filtration system in your home. Airborne particles can come into your living spaces from a wide variety of sources, and the size of these particles can vary substantially. As we mentioned, circulating your home's air through your furnace filter is a good way to minimize dust and miscellaneous airborne contaminants, but it can only do so much. There are certain types of particles that furnace filters are not able to capture, so using a HEPA filter can significantly improve the overall air quality in your home by scrubbing the air clean. For example, there are some airborne viruses that are extremely tiny, and can only be effectively trapped and contained using a HEPA-rated filter. As you can imagine, this particular benefit is certainly top-of-mind lately due to the effects of the recent COVID-19 pandemic. HEPA filters are a valuable tool in the battle against airborne viruses and other types of health concerns that may exist in the air.
Controlling airborne allergens is another important role that HEPA filters can play. Many people who suffer from allergies appreciate the efficiency with which an in-room or whole-home HEPA filter can affect their well-being. HEPA systems capture all common allergens with ease, including dust, pet dander, mold spores, pollen, and dust mites, to name a few. By substantially reducing the amount of allergen particles present in the air, HEPA filters provide excellent relief for allergy sufferers, and anyone who is prone to respiratory sensitivity, such as people afflicted with asthma.
Another thing that HEPA filters are used for is to control and remove airborne odours. Substances such as smoke or chemical vapours can be scrubbed from the air by filtering them through a HEPA system, leaving the air in your living spaces fresher and more comfortable. In fact, the surge in wildfires throughout many parts of Canada has increased demand for in-home HEPA filters as the harmful particles contained in wildfire smoke can be quite nasty if inhaled. If there are lingering odours in your home, or there are risks of wildfire smoke in your area, investing in a home HEPA filter system can be a wise move.
Choosing a HEPA Filter System
HEPA filter systems generally come in one of two styles; standalone single-room HEPA filters or whole-home HEPA filtration systems. Depending on your specific needs, an in-room HEPA filter may be sufficient to control the air quality in the room you spend the most of your time in. In-room HEPA filters are much more affordable these days than they were when they were first introduced to the market, and are widely available at most home stores and through local HVAC companies.
However, to ensure the best possible air quality throughout your entire home, a whole-home HEPA filter system integrated into your home HVAC system is the way to go. Naturally, these can vary greatly in price depending on the size of your home and the quality of the system, so be sure to shop around and get quotes from trusted and well-reviewed HEPA filtration system providers. The last thing you want is an air cleaner that doesn’t live up to the expectations, especially when the health of your family is at stake.
Regularly Replacing HEPA Filters for Optimum Performance
Regardless of whether you have a standalone in-room HEPA filter or a whole-home HEPA system, it’s critical to ensure that the filter in the unit is changed regularly. Just like your home furnace filter, as particles build-up in the filter, performance gradually reduces and it’s necessary to install a fresh filter to maintain air quality. For the specific time interval for replacing your HEPA filter, consult the owner’s manual, contact the installer, or visit the manufacturer’s website for technical support.
As a basic rule of thumb, most HEPA filter systems have a recommended filter change interval of about 6-12 months. Those HEPA filter systems that feature a carbon filter for better odour control must be changed a little more often, at around 3-6 months. These intervals can change based on the environmental conditions, so if your home is in an area that is prone to air quality warnings, you may want to shorten the filter change intervals accordingly to ensure your air stays clean and free of pollutants.
This is also important to be aware of as it relates to changing your home furnace filter. If you need to change your HEPA filter more often, you’ll definitely want to change your home furnace filter more often as well. Both systems work together to provide optimum clean air in your living spaces, so don’t neglect either one when it comes to installing a fresh filter. For more information on how often to change your home furnace filter, we recommend you check out our Guide to Furnace Filter Change Frequency to get the whole story and plenty of tips you can use.
We hope that you’ve found this information helpful! Don’t forget to browse around our other blog articles for more great tips and advice on how to improve your home air quality, save money on utility bills, and make the most of your HVAC system.
