Many people are concerned about the indoor air quality (IAQ) in their own homes. The cause for concern is understandable. Studies have shown that most homes have a poorer air quality than the air outdoors. For this reason, some homeowners have installed a higher tier air filter in their HVAC systems. One of the most popular choices is a HEPA filter, which would have only been found in medical facilities up until relatively recently. A HEPA air filter is certainly effective, but it may not be the best choice for every home.

What is a HEPA Filter?

A high-efficiency particulate air (HEPA) filter is an extremely effective mechanical air filtration method. The air filter is a pleated unit that can theoretically remove up to 99.97% of airborne contaminants, such as mold, pollen, dust, and more. A HEPA filter can remove particulate down to a size of only 0.3 microns, and they can even remove 95% of particulates down to 0.1 microns. To put this into some perspective, a micron is less than 1/25,400 on an inch in length. As you might imagine, this level of filtration is a very attractive option for any home where people with allergies or respiratory illnesses reside. A HEPA filter has a MERV (Minimum Energy Reporting Value) rating over 16, which is extremely high for a home.

The Importance of Air Filtration

Every HVAC system relies on a steady supply of air to work correctly. All of the air on our homes passes through the HVAC system many times over the course of the day. The air contains a number of airborne contaminants that have been collected throughout the home. As the air passes through the air filter, this material is left on the surface of the filtration media. Gradually, over time the filter becomes clogged with material, and this is why HVAC professionals recommend that the air filter is changed or cleaned every month. In fact, if you have pets, you may want to change the air filter every couple of weeks due to the collection of pet dander on the filter surface.

When the air filter is left clogged, it prevents the airflow leading to a number of issues. The main problem is that the lack of airflow can cause the HVAC equipment to overwork to maintain the airflow. This will result in extra stress and strain on the blower fan unit that pushes the treated air through your ductwork. In extreme cases, the blower unit can fail, leading to an expensive repair bill. Another issue is that the overworked equipment will consume more energy, and you will start to notice that your bills are rising.

Many homeowners believe that the regular air filter they use in their homes are designed to improve the IAQ. But, this is not correct. The main purpose of a standard air filter is to protect the HVAC components. When dirt, dust, and other debris gets into the sensitive parts of your HVAC system, this material can cause damage. A HEPA filter is quite different, but it suffers from many of the same problems as a standard air filter, which has become clogged.

HEPA Filter Issues

So, what does this have to do with HEPA filters? After all, they are more efficient than the lower MERV rating air filters discussed above. The dense material and pleated design of the HEPA filters is designed to remove very small particulates. If you think about it, that’s almost like the situation caused when a regular air filter is clogged. The airflow is lowered significantly because of the density of a HEPA filter.

If you install a HEPA filter in an HVAC system that cannot handle that level of air filtration, it will act like a standard air filter that has become clogged. The equipment will be overworked, leading to failures and even a premature replacement. The cost of your utility bills will rise because the system needs to work much harder to try and compensate for the lack of airflow. This is why a HEPA filter is not a great match for many homes, and their installation needs to carefully considered.

Up until recently, you only found HEPA filters in medical facilities or laboratories. Their installation was essential to maintain a cleaner environment to assist healing and get more accurate results during experiments. The first domestic applications for this technology were vacuum cleaners, followed by air purifiers and now whole house air filtration systems.

HEPA Filter Benefits

If you use HEPA filters in your home, the first people that will notice a difference are asthma and allergy sufferers. When the air is filled with mold, dust, and pollen, it can exacerbate or trigger allergic reactions. Although HEPA filters will not remove every airborne contaminant from your indoor air, they will make a significant difference to the IAQ. But, viruses, bacteria, and volatile organic compounds will still pass through because they are typically smaller than 0.3 microns.

Mold and HEPA Filters

A typical mold spore will range from 3-100 microns in size, so it will be trapped. But, most air filters contain a certain level of moisture that could allow mold to grow there. Eventually, the mold will spread throughout the entire filter, and mold may be released into the passing air. If you have a serious mold problem in your home, it’s a good idea to install an anti-microbial pre-filter to remove mold spores before they even reach your HEPA filter.

The Importance of Air Filter Labels

To be considered a HEPA filter, the filter must be able to remove at least 99.7% of airborne contaminants at 0.3 microns or more in size. Manufacturers make their filters to meet the Department of Energy (DOE) standards, and you will see them labeled as “True HEPA” or “Absolute HEPA” filters. If an air filter doesn’t meet these stringent standards, it’s likely to say “HEPA-like,” “HEPA-style,” or “HEPA-type” on the filter label. These will still be effective filters, but they are not as good as a “True” or “Absolute” HEPA filter design.

If you want to learn more about improving the IAQ in your home, contact your local HVAC specialist today.