An air filter is, no doubt, an important component of an HVAC system. It’s the component that’s responsible for keeping debris and air particles out of the system. Today, the air filter recommended by the US Department of Health is HEPA.
HEPA filters are recommended because they are 99.97% efficient when it comes to removing airborne allergens and pollutants. Apart from HEPA, there are many other types of air filters. They include UV light filters, electrostatic filters, washable filters, media filters, spun glass filters, and pleated filters.
What exactly is a HEPA filter and how does it work? Is a HEPA filter better than a regular filter? Are all air filters HEPA? These and more are the frequently asked questions that you’ll find answers to as you read through the rest of this post.
What is a HEPA Filter?
High-efficiency particulate air (HEPA) filter is a type of mechanical air filter that forces air through a fine mesh. It’s the mesh that traps harmful particles in the air, such as pollen, animal dander, tobacco smoke, and dust termites.
In case you don’t know, the working principle of HEPA filters is slightly different from other types of air filters out there. Yes, HEPA filters use four different processes to trap harmful particles in the air. These processes include impaction, Interception, diffusion, and sieving.
Speaking of impaction; this is the stage at which contaminants and harmful particles stick to the fiber, as air is being forced through the filter. The second stage, which is interception, occurs when harmful particles try to pass through the air filter but end up hitting and sticking to a fiber.
As for the diffusion process; it occurs when particles finally get stuck to one of the fibers after they’ve been bounced around by the air molecules. Sieving, however, occurs when the toxic particles eventually get stuck in between two fibers, especially when they are being forced through the filter.
High-efficiency particulate air filters are highly effective for trapping various harmful particles around the air in your home. These filters were recommended for every home by the US Department of Health. The recommendation came as a result of the fact that HEPA filters can trap and remove at least 99.97% of dust, mold, pollen, bacteria, and any other harmful airborne particles, which are as small as 0.3 microns in size.
Furthermore, the HEPA filters come with a Minimum Efficiency Reporting Value (MERV) rating of about 16. “16” is the highest level of the MERV rating and so, it means that HEPA filters provide the best results of all the different types of air filters out there.
Are All Air Filters HEPA?
No, all air filters are not high-efficiency particulate air filters. Instead, the HEPA filter is one of the several different types of air filters out there. Other types of air filters available out there include UV light filters, electrostatic filters, washable filters, media filters, spun glass filters, and pleated filters.
What exactly are these filters? Here’s what you need to know about them below:
UV Light Filters
Like the HEPA filters, UV light filters are air filters that utilize short-wave ultraviolet light to trap and kill bacteria and viruses in the air.
Here’s how a UV light filter works below:
- First, the air is allowed to pass through the HVAC system.
- Inside the HVAC system, there’s a UV lamp that helps to disinfect the incoming air with germicidal radiation. This way, all the harmful microorganisms, and mold spores in the air are trapped and killed.
One of the advantages of using UV light filters is that they are effective for killing stubborn pollutants trapped in the air around your home. UV light filters will help you eliminate pollutants, such as mold and germ, leaving you with high-quality indoor air.
However, UV light filters also have their weaknesses. One of them is that they are a little bit expensive to install when compared to other types of air filters. Moreover, the filters aren’t as effective as HEPA filters when it comes to removing more common pollutants in the indoor air.
Washable or reusable air filters are environmentally friendly filters. You don’t need to dispose of them every 6 months or 1 year. Instead, you can always use them for about 5 to 10 years, or even longer. Matter of fact, some manufacturers even claim that washable filters could last longer than the HVAC system itself.
Washable filters are economical, as they help to economically save money. However, you need to understand that the initial cost of investing in this HVAC tool is pretty high. Once you can afford the asking price, you won’t have to worry about changing your washable filter over and over again.
While washable filters are cost-effective, you need to understand that they aren’t without their issues. For instance, to enjoy these products, you need to provide them with regular maintenance. To do that, you’ll need to remove the filter, wash and then dry it regularly.
Electrostatic filters are very different from the other types of filters on this list. They work by creating static, using small cotton and paper fibers. The static created is what acts as a magnet, trapping and attracting dust and other harmful particles in your indoor air.
The electrostatic filter is one of the most effective tools that allergy sufferers can use to eliminate allergens from their indoor air. The static created by the filter is strong enough to attract the harmful particles in the air, keeping them from spreading across your indoor air.
Electrostatic filters are of two different types; disposable and reusable. Irrespective of the one you go for, what you need to know is that these filters are generally cost-effective.
However, the filters aren’t general-purpose. Instead, they are most effective for eliminating small particles. You may not find them helpful for removing larger particles, such as mold spores.
Like the rest of the filters on this list, media filters are effective for trapping tiny invisible air pollutant particles, such as animal dander, pollen, mold, and dust. The filters are usually installed on a return duct line. Any harmful particulates trying to enter your home are trapped immediately by this filter.
Furthermore, you need to know that using media filters comes with tons of amazing benefits compared to most filters on this list. You can say that they are as effective as high-MERV filters. The only difference, however, is that media filters perform the filtration process without you running into the issue of static pressure.
As effective as media filters are, they are ineffective when it comes to eliminating indoor air odor. Another setback of these filters is that they need to be professionally installed to deliver the best results.
A pleated filter is another type of air filter that you’ll find out there. This product often has a MERV rating between 5 and 13. One of the setbacks of this product is that they provide low air filtration. Apart from that, pleated filters are expensive and less resistant to airflow.
However, you can always use the filter to eliminate dust and other pollutants in your indoor air. This product often comes with a large surface area; as such, they are pretty much effective for eliminating debris.
Spun Flass Filters
Spun glass filters are made of strands of fiberglass. Unfortunately, these filters can only trap dust and lint. They aren’t effective for filtering smaller particles as they have a very small surface area. I wouldn’t advise anybody living with asthma to use spun glass filters because of their ineffectiveness to eliminate smaller particles.
Is a HEPA Filter Better Than a Regular Filter?
Like every other air filter, the HEPA filters have their strengths and weaknesses. The biggest advantage of HEPA filters over the regular ones is that they are more effective for purifying the air. These filters are designed specifically to trap and remove about 99.97% of dust, mold, pollen, bacteria, and airborne particles, which are about 0.3 microns in size.
One of the biggest differences between the regular filter and a HEPA filter can be seen from the materials used to construct them. For instance, the regular filters are usually made of porous materials, such as cotton paper sheets and polyester. As for HEPA filters; they are made of thin fiberglass material, as well as an activated carbon-based material.
How Do I Know if My Filter is HEPA?
The best way to check and understand that your filter is HEPA is by looking for the serial number and test results printed on it. If the test result, at 0.3 microns, is not up to 99.97 percent, it could mean that your filter isn’t HEPA.
Here’s the thing; for a filter to be HEPA, it has to be effective for eliminating at least 99.97% of dust, mold, pollen, and bacteria, especially those that are as small as 0.3 microns in size.