When it comes to indoor air quality, the air filter is one of the most valuable components of your HVAC system. So, how do you choose the right one for your system? In this article, we will explain the differences between various types of air filters, as well as some common terms like MERV rating and HEPA.
Why you need an air filter
The air is filled with dust and debris that can then be circulated and trapped inside your home. The air filter performs two vital functions to prevent that from happening.
- It protects your HVAC system from being damaged by circulating debris.
- It protects your indoor air quality by trapping allergens, dust, and other contaminants.
The MERV rating
The MERV rating measures how many particles the filter traps. MERV stands for Minimum Efficiency Reporting Value and is on a scale from 1-20, with 20 being the highest filtration possible. It’s important to note that filters with the highest MERV rating are not always best because along with trapping particles, they can also restrict airflow.
Types of Filters
Flat-paneled fiberglass air filters
Flat-paneled fiberglass air filters consist of a disposable filter made of layered fiberglass fibers. These inexpensive air filters mostly provide protection for heating and cooling components and not for cleaning the air.
They typically have MERV ratings of only 1 to 4.
Pleated media air filters
Pleated air filters with a medium efficiency rating can filter small to large particles. Ratings of 7 to 13 indicate a level of effectiveness compatible with absolute high-efficiency particulate air (HEPA) filters, but at a lower price point than HEPA.
These mid-range filters have MERV ratings of 5 to 13.
HEPA air filters
HEPA air filters are known for their high levels of air quality control. Recognized by the Occupational Safety and Health Administration (OSHA) and EPA as the ultimate product for removing airborne particles, HEPA products filter air at a very fine level, capturing contaminants and debris as small as 0.3 microns. These filters catch 99.97 percent of all particles. Most residential HVAC systems can’t accommodate HEPA filters because of their size (4 inches thick compared to the more standard 1 inch) and because they restrict more airflow. Switching to HEPA filters will significantly improve your indoor air quality, but doing so will probably require calling a heating and cooling professional as a true HEPA filter is not something that a homeowner can buy and use as a furnace filter. They need to be professionally mounted externally to the furnace.
HEPA air filters have a MERV rating of 17 to 20.
Washable air filters
Washable, or reusable, air filters require more complicated maintenance than simply replacing the filter. This type of filter can attract mold, and cost more than disposable filters. They tend to have only a 1 to 4 MERV rating.
For more information about air filters (which one is right for your home), as well as all your heating and cooling needs, contact the professionals at Indoor Air Quality today! IAQ serves homeowners in Highlands Ranch and the Denver Metro area.