HVAC filtration is one of the most crucial components in maintaining your home’s indoor air quality. With multiple types of filters on the market, you may have trouble determining which one is best for your home. Fortunately, homeowners can quickly address indoor air quality concerns by learning about HVAC filters and the various types available.
Understanding Efficiency Ratings
The Minimum Efficiency Reporting Value (MERV) is the standard for rating the performance of filters. The scale ranges from 1 to 20, indicating the effectiveness of a filter in capturing fine particles. The higher the MERV rating, the more effectively the filter removes fine particles from the air. This is because the mesh is more tightly woven, trapping more particles. However, the tight weave also restricts airflow, so higher MERV-rated filters may require a more powerful motor to push the air through the filter.
It’s essential to note that installing a higher MERV filter in a system isn’t always the solution. Many furnaces, for example, require low-MERV filters to maintain airflow. Adding a high-MERV filter in the furnace configuration can starve the fire of oxygen, significantly harming its performance. If an HVAC doesn’t support high-MERV filtration, the solution is typically to add a separate unit along the air return for air purification.
Likewise, be aware that filter costs tend to rise with MERV ratings. One of the reasons for using cheaper filters is to reduce the costs associated with running the system.
Fiberglass Filters
Normally rated in the MERV 1-4 range, fiberglass filters are standard intake filters for many furnaces. They also often serve as pre-filters on purification units. Spun glass fibers sit on a lightweight aluminum wire mesh to provide the minimum capability to capture large particles. This keeps things like hair, lint, and larger bits of dander out of the system. They can also capture some pollen and dust mites, but not at a high rate of efficiency.
Pleated Filters
Pleating a polyester or cotton surface increases the surface for capturing particles by as much as tenfold. These types of filters typically have MERV ratings of 5-13, enabling them to capture most dander and mold. Many brands may also have electrostatic charges to increase the attraction of particles to the filter medium.
HEPA Filters
High-efficiency particulate air filters are 99.97% efficient at capturing particles as fine as 0.3 microns from the air. This is more than 200 times smaller than the typical human hair. It is also the range at which you would have a high expectation of capturing most bacteria and many viruses. HEPA filters utilize a dense structure of microfibers to maximize capture efficiency.
One notable aspect of using a HEPA filter is that it requires more air pressure to operate properly. Integrating HEPA filters into an HVAC system, even as part of a purification unit, requires more planning than simpler systems do.
UV Light Filters
UV light is one major air filtration method that doesn’t push the air through a material. Instead, a bulb emits UV-C (germicidal UV) light that breaks down the DNA of bacteria, viruses, and other pathogens in the air. Air in the ductwork flows past the installed bulb, which bombards and disrupts contaminants. This results in a reduction of more than 99% in bacteria and viruses in a home’s air within approximately 24 hours.
Activated Carbon Filters
Also referred to as an activated charcoal filter, activated carbon filters react to chemicals and odors in the air. A porous carbon surface provides a surface for chemicals to bond to and react with. The carbon neutralizes the chemicals, significantly improving air quality.
Combining Filters
The most effective way to enhance indoor air quality is to utilize a combination of filters. With multiple ways for problematic contaminants to get caught or neutralized, the odds are much higher that a combined solution will provide more breathable air.
You can avoid purchasing unnecessary products by thinking about your household’s specific needs. A household with a good dehumidifier but lots of pets might be more worried about controlling dander than killing mold, for example. They might consider a combination of fiberglass and pleated filters to reduce the spread of pet dander. Someone more concerned about allergies could focus on HEPA filtration to capture pollen that has entered their house.
Putnam Mechanical serves the people of Charlotte, NC and the surrounding areas. We install, repair, and maintain HVAC systems. To learn how various types of filters can benefit your Charlotte home’s HVAC system, contact Putnam Mechanical today. Ask us about our maintenance plans!
