Key Differences Between HEPA & MERV Filters
Air filters prevent impurities in the air from entering your HVAC system, and choosing the right type of air filter can help improve indoor air quality and HVAC efficiency. In today’s post, local HVAC repair company Schmitt discusses two of the most common types of air filters: HEPA and MERV filters.
Minimum Efficiency Reporting Value, or MERV, is a rating system that describes an air filter’s efficiency. MERV ratings are represented by numbers between 1 and 16. The higher the MERV rating, the better it is at blocking impurities in the air. The term “MERV filter” refers to air filters that bear MERV ratings; this is an important distinction, as not all air filters are rated.
MERV filters are classified into two types:
Flat-Paneled Fiberglass Filters — These are the low-cost air filters that most people are familiar with. The media, or the layer of material used for filtration, is made of several layers of fiberglass reinforced by a metal grate. As the “default” type of air filter, a flat-paneled fiberglass air filter typically has low-to-middle MERV ratings. It can filter relatively large particles like hair and carpet fibers and is sufficient for most applications.
Pleated Media Filters — Pleated media filters are rated higher than flat-paneled air filters and typically meet or exceed air conditioner manufacturer requirements. Instead of flat panels, they feature pleated media, which allows for better filtration. AC repair technicians recommend pleated media filters as an ideal upgrade because they strike a good balance between cost and efficiency.
High-efficiency particulate air (HEPA) filters aren’t MERV-rated because they exceed the highest filtration standards required for such ratings. The media used for HEPA filters are so fine that their minimum efficiency is 99.97%; as such, they can filter particles as small as 0.3 microns. In comparison, the average dust particle is 20 microns.
Which One Is Best for Your HVAC System?
At first glance, it seems like the obvious choice would be the more efficient air filter. But you should consider that the higher the MERV rating, the more dense the media will be, therefore the higher the resistance to airflow. Residential air conditioning systems come with a list of recommended MERV ratings; simply choose the air filter with the highest rating recommended by the manufacturer. HEPA filters, while much more efficient, are ideally used in hospitals and other kinds of buildings that require near-sterile air and have the appropriate kind of air conditioning systems.
Call Schmitt for Your Air Conditioning Needs
Schmitt is your leading provider of air conditioning and heating repair services. Give us a call at (415) 689-7849. You can also fill out our contact form to schedule an appointment. We serve customers in San Francisco and surrounding communities.