Indoor air quality has declined over the past generation. Houses are built tighter, sealing in emissions from synthetics in building materials like composite woods, plastics, finishes, sealants, adhesives and carpets, and from cleaning, personal and craft products. These accumulate to create what some environmental experts call “chemical soup”. An EPA study indicates that air is more polluted indoors than outdoors. The problem is significantly worsened by particulate pollutants. Magnification of typical unfiltered indoor air reveals often alarming densities of wide-ranging contaminants, including spore chains and other fungal matter, dust mites, insect parts and fecal particles, pollen, dander from people and pets and viral contaminants. Of air filtration media designed to remove particulates, HEPA filtration achieves the highest efficiency.
What is HEPA filtration?
High Efficiency Particulate Air (HEPA) is a general class of efficiency in mechanical filtering that has been rated as such by the Institute of Environmental Sciences and Technology. In order to be defined as HEPA, an air filter is required to capture nearly 100 percent of airborne contaminants of the 0.3 microns size. However, HEPA filtration is proven to be very effective in capturing particulate smaller than required. And, U.S. Department of Energy standards applied to HEPA rated filters are much higher than for filters assigned high MERV efficiency ratings. A "true HEPA filter" must achieve a MERV rating of 17-20 with a particle arrestance rate of more than 99.97 percent.
The HEPA filter is constructed of a very fine mesh of fiberglass fibers. The sophisticated design incorporates of all three of the typical filtering processes – interception, impaction and diffusion for exceptional efficiency in particle arrestance.
How are HEPA Filters Different From Other Air Filters?
- Pleated filter – This filter is a disposable cotton-polyester blend with a light cardboard frame. It usually achieves a MERV rating of approximately 7 because its arrestance efficiency is greater than 90 percent.
- Cartridge filter – A synthetic cube coated with viscous material, cartridge filters receive MERV ratings of approximately 6 with an arrestance efficiency of 85-90 percent.
- Throwaway filter – This disposable synthetic media receives a MERV rating of approximately 5 with arrestance rates of 80-85 percent. Lesser quality versions of these filters have MERV ratings of 3 due to lower arrestance rates between 70-75 percent.
- Washable filter – Aluminum mesh filters receive MERV ratings of about 2 with arrestance of 65-70 percent. This type is sometimes used in window-mounted air-conditioning units.
- Electrostatic filter – This is a self-charging panel filter of woven media. The MERV rating is commonly around 1 because it is reliable for; less than 65 percent arrestance of particulates.
What Are the Health Risks From Indoor Air Pollutants?
For small children, the elderly, and any person with respiratory sensitivity or medical conditions that compromise immunities, efficient air filtration is essential. And, anyone living with very poor can experience a variety of symptoms, including the following.
- Eye redness
- Irritated throat
- Allergic reactions
- Lung Irritation
- Nose running, sneezing
- Skin rashes
- Asthmatic episodes
- Cold-like or flu-like symptoms
- Increased COPD symptoms
When Is It Advisable To Use HEPA Filtration?
If tolerance by members of your household to airborne particulate contaminants could become reduced due to any of the following conditions, HEPA filtering may be the best solution.
- An occupant has respiratory sensitivity
- Relatively high levels of outdoor pollutants are present
- Poor air-tightness in older home – outdoor pollutants excessively impacting indoor air quality
- Home has a wood-burning fireplace
- An occupant smokes
- A large amount of cooking is done in the home
- Multiple human or animal occupants
- Construction material types or grades in new home OR materials for craftworks cause poor air quality, potentially compromising occupants' tolerance of particulate type pollutants
- Removal of viral particulates is a priority
When May HEPA Not Be the Best Solution?
An HVAC professional should determine whether or not your HVAC system is sturdy enough to support HEPA filtration. Most home systems aren't built to handle HEPA filters and can become excessively strained, resulting in fan motor damage or failure due to the increased level of airflow resistance. Older HVAC systems should use filters with MERV ratings of 11 or lower; very old systems need filters rated 8 or lower. The oldest need filters causing the least airflow resistance, but such filters don't provide much filtration and have severely low MERV ratings. If HEPA filtration is necessary, your HVAC contractor may be able to install a system in your ductwork to divert air through the HEPA filter, then send the filtered air back into normal circulation.
Please contact us at Comfort24-7 for more information about HEPA filtration. We proudly provide affordable services to our customers across Chicagoland and counties in Southwest Michigan and Northwest Indiana, including Porter, Kendall, Kankakee, Winnebago, LaPorte, Saint Joseph, Kane, McHenry Berrien, DeKalb, DuPage, Lake, Will, Boone, Newton, Grundy and Cook.