How Are Furnace Filters Rated?

Even in the Southern California heat, there can be some chilly nights in the winter. You need to make sure that your furnace filter is in working order. When it comes time to replace this important element, do you know how to choose the right filter? 

Furnace filters are rated on a specific scale that tells you how effective they will be cleaning your air. This scale is known as the MERV scale, and this article will look at how it works. 

What System Rates Furnace Filters?

How do you know which type of furnace filter your home needs? It starts by paying attention to the rating system used to measure these filters. They are rated on a scale known as the Minimum Efficiency Reporting Value (MERV). Scores range from 1 to 20, with higher numbers indicating a filter that can trap smaller particles. 

Each range on the MERV scale is best suited to a particular application: 

  • MERV 1 to 4: Residential window AC units
  • MERV 5 to 8: Improved residential, commercial, or industrial areas
  • MERV 9 to 12: Best residential, improved commercial, and hospital laboratories
  • MERV 13 to 16: Hospitals and operating rooms
  • MERV 17 to 20: Electronics or pharmaceutical manufacturing

There is no need for you to search for furnace filters at the higher end of the MERV rating scale. These higher-level filters are ideal for certain applications, but they are not practical for a residential setting. 

What MERV Filter Rating Do You Need? 

Most homeowners have a difficult time figuring out what rating to purchase for their homes. How do you decide what rating is right for you? 

Experts recommend looking for a filter with a minimum rating of four. This rating will help to filter out common allergens such as pollen, dust mites, sanding dust, spray paint dust, and carpet fibers. At this lower level, you will spend the least amount of money on your filter. 

However, this low rating may not be ideal if you have pets or allergies. Filters with a MERV rating of five to eight are better equipped to filter out cat and dog dander, mold, spores, dusting aids, and more. A rating of seven to eight will be reasonably priced, and this is all most homeowners truly need.

Consider going higher only if you have a history of health issues or severe allergies. You can look for something more in the 9 to 12 range to filter out smaller particles that may cause problems for your health. 

Can You Go Higher on the MERV Scale?

Are you tempted to go as high as you can with your next furnace filter? Be careful that you do not exceed the maximum MERV rating for your furnace. This information should be available in your owner’s manual. 

The problem with higher ratings is that they filter more of the air, restricting the airflow through your furnace. This restriction can make your system work harder than necessary and lead to higher bills and more frequent repairs. You will not be able to effectively heat your home if your air filter is restricting too much airflow. 

Help Replacing Furnace Filters

If you need help selecting the right furnace filter, trust the experts at Rowland Air. We are here to answer any questions you may have about your furnace filter and how to replace it with a filter with the right rating for your home, or other HVAC regular maintenance issues