Have you ever taken a close look at your HVAC filters when replacing them? If so, you may have noticed that each filter has a MERV rating – and this number has important implications.

TL;DR – What to Know About Air Filter MERV Rating

  • MERV (Minimum Efficiency Reporting Value) measures how well HVAC filters remove particles from the air.
  • Higher MERV ratings mean better filtration but require stronger HVAC systems to handle denser filters.
  • Using a filter with too high a MERV rating can strain your system, reduce efficiency, and lead to costly repairs.
  • Check your HVAC system's documentation for the recommended MERV range to avoid issues.

What Does MERV Stand For?

MERV stands for “minimum efficiency reporting value” and the MERV rating is a measure of how effectively a filter removes particles from the air that passes through it. The higher the MERV rating, the more particles the filter will catch.

There’s a flipside to this, though. Filters with higher MERV ratings generally feature denser filtration material, which means more force is required to push air through the filter. It takes exceptionally powerful HVAC fans to effectively push air through the filters at the high end of the MERV rating scale.

What MERV Rating Do I Need for Furnace/HVAC?

If you use a filter with a too-high MERV rating in your home HVAC system, it could have the effect of using a dust-clogged filter – air struggles to push through, which puts accelerated wear on your system’s fan and other components. This leads to more frequent service and repairs.

To make more thoughtful decisions about what type of filter to use in your home HVAC system, start by checking your system’s documentation for a maximum MERV limit. Using filters above the MERV limit will hurt your energy efficiency immediately and will likely cause more expensive problems down the line.

Once you know your available range of MERV ratings, consider whether there are signs you might need more filtration than you currently enjoy. Are there allergy or asthma sufferers at home? Do you have a shedding pet? Does your home seem abnormally dusty? If the answers to any of these questions is yes, you may be able to find some relief by upgrading to a filter with a higher MERV rating.

MERV Rating – By The Numbers

MERV ratings range from 1 to 20. In residential HVAC systems, filters in the 1-4 range are most common, but it’s not unheard of for homeowners to use filters with MERV ratings as high as 8 in typical household systems. Here’s a quick rundown of what filters of various MERV ranges are capable of filtering out of the air:

MERV 1-4

These filters catch large particles: dust, dust mites, pollen, carpet fibers, insects and some of their waste. MERV 1-4 filters are primarily used in residential HVAC systems.

MERV 5-8

These filters are used in some homes and in most commercial and industrial settings. MERV 5-8 filters can catch finer dust particles, mold spores, aerosol spray particles and pet dander.

MERV 9-12

Rarely used in residences, MERV 9-12 filters are common in certain commercial buildings and in some hospital laboratories. They can capture automotive emissions, welding fumes, lead dust and larger bacteria.

MERV 13-16

These heavy-duty filters are typical in hospital surgical centers and other areas where heavy filtration is paramount, such as smoking lounges. MERV 13-16 filters collect a larger range of bacteria, smoke particles, oil droplets and fine particles from sneezing.

MERV 17-20

At the top of the scale, MERV 17-20 filters are used in clean rooms where pharmaceuticals and sensitive electronics are produced. They can catch viruses, carbon dust and the smallest smoke particles.

Types of Residential Air Filters

Fiberglass Filters

  • Affordable and disposable.
  • Low filtration efficiency (MERV 1-4).

Pleated Filters

  • Higher efficiency for allergens and dust (MERV 5-13).
  • Common brands: Honeywell, Filtrete by 3M.

Electrostatic Filters

  • Attract particles using static electricity.
  • Washable or disposable options.

HEPA Filters (High-Efficiency Particulate Air)

  • Captures 99.97% of particles ≥0.3 microns.
  • Common in air purifiers and HVAC systems for allergy sufferers.

Specific Air Filter Models

  • The 9223 A889 20402 air filter is commonly used in specific HVAC systems and air purifiers. It effectively captures particles like dust, pollen, and pet dander, enhancing indoor air quality. 
  • The 22U-04-21261 is a filter element designed for use in Komatsu machinery, specifically in their construction and heavy equipment lines.

While the highest-rated MERV filters are rarely necessary for most households, understanding indoor air quality services is essential. Upgrading your filter and pairing it with duct cleaning services can significantly improve air quality, boost HVAC efficiency, and reduce allergens, dust, and other contaminants in your space. To get started, reach out to an HVAC professional near you today,