Studies have shown that many of us have an indoor air quality (IAQ) that is worse than the polluted air outdoors. The recent Covid-19 pandemic has also worried many homeowners and this increased the interest in indoor air cleaning technology. There are many ways to clean air and one of the more popular methods is HEPA filters. Improving IAQ leads to fresher air that’s easier to breathe and it can relieve the effects of many respiratory ailments. Let’s take a closer look at some of the issues related to the installation of HEPA filters in your own heating and cooling system.

What are HEPA Filters?

A High-Efficiency Particulate Air (HEPA) filter is the current standard for mechanical high quality air filtration. HEPA filters are often used in laboratories, clinics, clean rooms, and other sensitive locations where the air quality must meet high standards. A good HEPÂ filter can remove around 99.97% of airborne particulates from the air. The means that the only particles that could pass through a HEPA filter would be 0.03 microns in size! These types of air filters can remove many microscopic particulates, including dust, mold, pet dander, and more. This level of filtration performance is possible because of the dense nature of HEPA filters.

The History of HEPA Filters

The origins of HEPA filters date back to World War II when they were developed as a safeguard for scientists working on the Manhattan Project to develop the first Atomic Bomb. Thin layers of fiberglass mesh were assembled together to create a surface with unparalleled filtration properties at that time. Even today, HEPA filters offer outstanding filtration efficiency and the design has improved significantly over the years.

What About Standard Air Filters?

The standard air filters used in HVAC systems do capture some airborne particulates, but they are not up to the standard of HEPA filters. The primary purpose of these air filters is to prevent larger particulates from entering and damaging sensitive HVAC components. Relying on a standard air filter to clean your air is not an effective strategy even if you are changing them regularly as recommended.

Should I Install HEPA Filters?

Although HEPA filters are very effective at cleaning the air and they will improve the IAQ it’s important to exercise care when considering their use. These filters are extremely dense and it’s very hard to force air through them efficiently. In fact, most homes simply don’t have a sufficiently powerful motor to maintain the airflow through HEPA filters. This will lead to two main problems, they are:

1.   Diminished Airflow

The HVAC system relies on good airflow through the system during operation. If the airflow is impeded it can cause components to be overworked which can lead to failures and maybe an earlier than expected replacement. This is why it’s extremely important to change even standard air filters regularly and full details are in your owner’s manual.

2.   Higher Energy Bills

When an HVAC system is overworking to force air through a dense HEPA filter it will consume more energy. This will be reflected in higher than expected utility bills that can really add up over time.

Most residential HVAC systems are simply not powerful enough to force air through HEPA filters. Medial or commercial systems are larger, more powerful, and can be designed to work with these denser mechanical filters. So, what can you use to improve the IAQ if you cannot use HEPA filters in your home? Let’s take a look at MERV ratings and some filtration alternatives that may be a good fit for you.

Understanding MERV Rating

The Minimum Energy Efficiency Reporting Value (MERV) rating is a simple way to evaluate the various types of air filters available for use. In simple terms, the scale runs from 1-20 and higher numbers indicate better levels of filtration. At the upper end of the MERV rating scale, there are filters that are extremely effective at capturing microscopic particulates. To put things in perspective, let’s take a look at some common filters types and their relative MERV rating in ascending order, they are:

  • MERV 5: Standard Flat Filters that can remove dust mites and pollen.
  • MERV 8: Pleated Air Filters that can also remove mold spores.
  • MERV 13: Box Air Filters that remove the above and certain gas fumes.
  • MERV 14-20: Air Filters that are used in medical facilities, laboratories, and industrial applications.

The HEPA filters that you may be considering for use in your HVAC system typically have a MERV rating of 17-20. As you can see, this puts them near the top end of the scale which cleans the air to a standard that is probably overkill for residential use.

What is the Highest MERV Rating for Home Use?

Most homes have an HVAC system that can handle a MERV rating of 13. If an air filter with a higher MERV rating is installed, it can cause the two problems that we mentioned earlier. If you have the need and budget, it is possible to use HEPA filters as part of a whole-home filtration system. This equipment is located in the ductwork system and the utility bills will be higher when using this type of system in your home.

Can the IAQ be Improved without HEPA Filters?

Yes, it is possible to improve the IAQ in your home without using denser filters that can cause other problems. Two of the more reliable methods are activated carbon filters and ultraviolet (UV) germicidal lights. Activated carbon filters are effective at removing odors, such as cooking smells, tobacco smoke, and more. UV germicidal lights are effective at destroying airborne microorganisms such as bacteria and mold. Only ten seconds of exposure to UVC light is sufficient to destroy the ability of microorganisms to replicate. These two methods are typically used together in series to clean the air and improve the level of comfort in your home.

Choosing a HEPA Filter

If you opt for a HEPA based air filter there are few choices, they are HEPA filtration, media air cleaners, and air filtration systems. HEPA is the more effective method and it typically has a multistep process to remove larger and then increasingly smaller particles. The media air cleaner system uses a filter in combination with activated carbon filters. The air purification system uses all of the above with a MERV rating of 16 which is equivalent to a well equipped hospital.

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