How to Select the Right MERV Rating for Your Furnace Filter

Determining the right MERV rating for your furnace filter can be tricky. There are various types of filters to use, and it might be hard to select a filter that best suits your needs. We’re here to help. A1 Chesney Service Experts is your local HVAC Expert in Calgary, assisting you in making smart decisions for your home.

Getting the right furnace filter is all about balancing indoor air quality with your HVAC system’s capabilities. Finding filters with the right MERV ratings is critical to ensuring your air is healthy without overly taxing your HVAC system.

What Does MERV Mean?

A minimum efficiency reporting value, or MERV is a measurement system created by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE). MERV ratings denote an air filter’s effectiveness at decreasing airborne particles and contaminants. A filter’s rating is determined by the minimum size particle it’s capable of capturing (measured in microns). As filters become better at improving indoor air quality, their MERV rating goes up, ranging from 1 to 20.

Below, you will find a chart that can help you determine the necessary MERV rating for a variety of applications.

MERV Range Controlled Contaminants Typical Application Air Filter Types
1-4 Pollen, Dust, Spray Paint, Dust Mites, Sanding Dust, Textile & Carpet Fibers Residential, Window AC Units Disposable Electrostatic
5-8 Mold Spores, Pet Dander, Hair Spray, Dusting Aids, Fabric Protector, Cement Dust, Pudding Mix Better Residential, Commercial, Industrial Workplaces Pleated Filters Cartridge Filters Electrostatic
9-12 Legionella, Auto Emissions, Lead Dust, Humidifier Dust, Welding Fumes Superior Residential, Better Commercial, Hospital Labs Pleated Filters Cartridge Filters
13-16 Bacteria, Droplet Nuclei (Sneeze), Tobacco Smoke, Insecticide Dust General Surgery, Hospital Inpatient Care Bag Filters Box Filters
17-20 Viruses, All Combustion Smoke, Carbon Dust Cleanrooms, Radioactive & Carcinogenic Materials, Pharmaceutical Manufacturing HEPA Filters Specialized Filters

Other Measurement Systems

Familiarity with MERV ratings might not be enough when you need to buy your furnace filter. For example, some major retailers use the filter performance rating (FPR), which ranges from 1-10 and measures a filter’s ability to trap large and small particles. You might also see the microparticle performance rating (MPR) system, which goes from 300 to 2200 and measures a filter’s effectiveness at capturing only the smallest particles on the MERV scale (0.3-1 microns in size).

You can use the chart below to better understand how filters rated with FPR and MPR stack up to the more standard MERV rating system.

MERV Rating FPR MPR
MERV 1-5 Below Minimum FPR Below Minimum MPR
MERV 6 Below Minimum FPR MPR 300
MERV 8 FPR 5 MPR 600
MERV 11 FPR 7 MPR 1000-1200
MERV 13 FPR 10 MPR 1500-1900
MERV 14-20 Above Maximum FPR MPR 1900+

What Should My Furnace Filter’s MERV Rating Be?

Choosing the right MERV rating for your air filter is a delicate balance between your HVAC system’s capabilities and the indoor air quality you want to achieve.

For example, a higher MERV rating doesn’t always mean that a filter is the best choice for your furnace. In fact, as MERV rating increases, air flow goes down—forcing your HVAC system to work harder to move air through your furnace, increasing the likelihood of a potential breakdown. Before purchasing a new furnace filter, be sure to check if your HVAC system has a limit for MERV rating. If it has one, be sure to get a furnace filter with a MERV rating that’s lower than your system’s maximum.

If your family has allergies or serious respiratory issues like asthma, you may want to get filters with higher MERV ratings. Remember, there are always other options out there to improve your indoor air quality if your system is unable to handle the MERV ratings you need.

Generally speaking, our recommended MERV rating for furnace filters runs from 6 to 8 for a fantastic balance between maximum furnace efficiency and home comfort.

Selecting the right MERV rating for your furnace filter has a huge impact on your indoor air quality, your HVAC system and, most important, your family’s health. Let A1 Chesney Service Experts help you make a smart decision. We have a full line of air filtration solutions plus our Expert knowledge and service—and we’re available 24/7 for emergencies. Contact us at 866-397-3787 to request your indoor air quality consultation in Calgary today!