MERV Rating Guide and your Home's Air Filters

MERV Ratings

What is MERV?

MERV, or Minimum Efficiency Reporting Value, is a rating system developed by the American Society of Heating in order to gauge filter effectiveness. The higher MERV values an air filter has the more air contaminants that filter is able to protect a ventilation system from. MERV ratings also help dictate how much energy is going to be needed for the ventilation system to work at full efficiency. Air filters determine air flow and affect monthly energy bills.

Importance of MERV and the Different Levels

Higher MERV equals higher levels of protection, but also a greater strain on air flow. When an air filter is too restrictive or dirty the air flow is affected, causing malfunctions or a rise in costs. Higher MERV rated filters are only used for extremely high maintenance and sanitized buildings, not homes. The setting of a filter determines the MERV rating required for air and furnace filters to function properly.

What is MERV in Air Filters?

An air filters MERV rating helps rate the holes in a filter that capture passing by dirt and debris. The smaller a filter’s holes, the more it is able to capture, and the higher its MERV rating will be. When a filters MERV rating is too high this actually restricts the air flow and causes system issues. Higher MERV-rated filters are suggested for larger, more sterile facilities rather than home.

Recommended MERV Rating for Furnace Filters

For the average home a filter settling near the center of the MERV chart is considered more suitable. When a home has an appropriately rated filter installed, this provides multiple benefits. The air flow through a ventilation system requires less energy with lower MERV rated and clean air filters. Lower rated MERV filters also need to be cleaned less often.

MERV 8

A filter rated at level 8 on the MERV scale is commonly used for better than average residential homes, industrial workspaces and commercial buildings. This level of MERV air filter is capable of blocking:


  • Debris
  • Dust Mites
  • Dirt
  • Mold
  • Spores
  • Pet Dander


MERV 11

The filters in the MERV 11 category are used for more sanitary areas and homes. The air filters are capable of keeping the air of places like hospitals and other high-sanitation buildings clean. Filters with this rating are used to block out:


  • Auto-Emission Particles
  • Debris
  • Dust Mites
  • Dirt
  • Lead Dust
  • Milled Flour
  • Mold
  • Nebulizer Drops
  • Spores
  • Pet Dander


Air filters with this level are often reusable and made from sturdy materials allowing for washing and reuse.

What is MERV Rating for Furnace Filters?

A furnace filters MERV rating helps determine the filters ability to protect the blower fan. The air filters purpose to prevent contamination and help air quality, not actually clean the furnace. Higher rated MERV filters can be dangerous to have on filters due to there being a higher chance of affected air flow. If the airflow in a system is affected by high MERV-rated or dirty filters then this could lead to furnace issue and possible damage.

Furnace Filter Recommended Ratings

The best MERV level for a furnace is when the air filters are at levels like 4, 7, and 8. A higher MERV level prevents easy air flow, causing a buildup in non-industrial powered systems like those in industrial or high commercial buildings. Furnace filters at level 4, 7, and 8 are capable of preventing dust mites, mold spores, hair spray, pollen, textile fibers and more. The filters lower MERV level allows flow to pass through more easily and requires less regular maintenance.

Contact the Air Filter Provider Able to Provide High MERV Rated Products

When you are looking for quality furnace filters for your home or business, then Filter King is able to provide just what you need. We sell air filters at affordable prices in a variety of sizes to fit any location. You can also buy the subscription package, where the filter is brought straight to your door, ready for replacement. Call today and start talking about replacing your air filters at great prices you can afford.