What You Need To Know About MERV Ratings

Have you ever taken a closer look at your HVAC filters when replacing them? If yes, then you may have noticed that each filter has a MERV rating and this number has important implications. MERV stands for “minimum efficiency reporting value” and the MERV rating is a measure of how effective it works. The higher the MERV rating, the more effective it catches particles.


However, the tricky side to this though is the higher the MERV ratings also means the more dense of material it filtrates and the more force it requires in order to push air through the filter. In addition, it takes exceptionally powerful HVAC fans to effectively push air through the filters at the high end of the MERV rating scale.


On the other hand, if you use a filter with a too-high MERV rating in your home HVAC system, it could lead to a dust-clogged filter. The air will struggle to push through, which puts accelerated wear on your system’s fan and other components. This could eventually lead to more frequent service and repairs.


Start by checking your system’s documentation for a maximum MERV limit to make more thoughtful decisions about what type of filter to use in your home HVAC system. Continuous use of 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 ratings range from 1 to 20. The most common is 1-4 for residential HVAC systems , 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 list of what filters of various MERV ranges are capable of filtering out of the air:

MERV 1-4

Primarily used in residential HVAC systems. These filters catch large particles: such as dust, dust mites, pollen, carpet fibers, insects and some of their waste.

MERV 5-8

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

MERV 9-12

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

MERV 13-16

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

MERV 17-20

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


Curious about what type of filter you should be using at home? You can check with your local HVAC professionals at Builder’s Heating & Cooling for expert advice. Call us today at (708) 375-5228.