The filter plays a vital role in keeping your HVAC system operating properly, but the confusing ratings used for air filters can make it hard to know which one to choose. Here’s a helpful overview of industry acronyms and how the HVAC air filter rating system works.
MERV — The Filter Efficiency Standard
The standard rating system used for air filters is known as MERV, or minimum efficiency reporting value. This numbered rating describes a filter’s ability to capture particles in a specific size range. The rating scale increases from 1 to 20 according to filter effectiveness.
What are HEPA Filters?
HEPA stands for high-efficiency particulate arrestance, and these filters are at the top of the MERV scale with ratings between 17 and 20. True HEPA filters can capture particles down to 0.3 microns in size, and they’re up to 99.97 percent effective. These filters are very resistant to airflow, so they’re not suitable for home HVAC systems.
Which Filter is Right for Your System?
If you’re not sure about which filter to go with, check the rating range recommended by your equipment manufacturer or ask your HVAC technician for advice. Here’s a look at where some commonly-used HVAC filters fall on the MERV scale.
- Flat filters — These basic fiberglass filters have ratings between 1 and 4, and they can trap roughly 80 percent of particles bigger than 10 microns. They’re not very effective at cleaning the air, but they can protect sensitive components by keeping large harmful particles out of the HVAC system.
- Pleated media filters — These filters are considered medium-efficiency with ratings from MERV 5 to 13. Those with higher ratings can trap up to 95 percent of airborne particles from 1.0 to 3.0 microns so they do a better job of improving air quality.
- Higher-efficiency filters — Thicker pleated filters with ratings between 14 and 16 are available but to use one, your HVAC pro will likely have to modify your system to ensure ample airflow.
For advice about which HVAC air filter is ideal the system in your Lorain home, contact us at Energy 1 Heating & Air Conditioning.
Our goal is to help educate our customers in Lorain, Ohio about energy and home comfort issues (specific to HVAC systems). For more information about air filter ratings and other HVAC topics, download our free Home Comfort Guide or call us at 440-201-2959.
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