Why your MERV rating matters

May, 5 2020
This couple is struggling to find the correct MERV size for their HVAC furnace filter.

Ever found yourself standing in a store looking over your air filter options with no idea how to choose the right one? Luckily, we are here with a little guidance, so you’ll feel confident the next time you purchase an air filter for your home.

What is MERV?

MERV, or the minimum efficiency reporting value, is a measurement of how effective an air filter is at removing dust and debris from the airstream. Filters come in a variety of MERV ratings, from 1 to 16. So, is it true that the higher the MERV rating, the better the filter? Not necessarily – a higher MERV rating means a couple of things:

  • Filter is more effective at removing particles from the air.
  • Filter will require more energy to force air through that filter and into the rooms in your home, and it could also tax your HVAC system.

AAF Flanders MERV rating chart.

Cats and pets can contribute to IAQ.What factors should I consider?

If buying filters with the highest MERV rating isn’t always the best solution, then you need another way to determine which MERV rating works for you and the people in your home. Assess your needs using these helpful questions before upgrading your filter.


  • Does anyone in my family have mild to severe allergies?
    • If yes, are the allergies seasonal or year-round?
  • Does anyone suffer from asthma symptoms?
  • Is my home old or drafty?
  • Are there any other property issues that might affect IAQ (indoor air quality)?
  • Do you have a pet or pets?
  • Does anyone in or around the household smoke?
    • Put another way, even if your family doesn’t smoke, do you have a nearby neighbor who smokes?

If you feel uncertain, ask yourself these questions before purchasing a new air filter for your home. As a rule of thumb, experts suggest that most residential HVAC systems opt for a MERV rating between 7 and 12. Filters within this MERV range remove common contaminants such as pollen, mold spores, dust, pet dander, and tobacco smoke without placing unnecessary strain on your HVAC system or running up your energy bills.


How do I care for my air filter?

Most people tend to forget about air filters shortly after installing them. However, these filters help ensure clean air for you and your family to breathe. To maximize the cleanliness of the air in your home and the life of your filter:

  • Check your filter regularly. When you hear your HVAC system running, typically in winter and summer months, it is a good idea to check you filter even more frequently. Because it is easy to forget to check, we suggest setting yourself a reminder (OR REGISTERING YOUR FILTER FOR A REMINDER).
  • Change your filter at regular intervals. While extending the length of time that a filter is in use can save money on filters, it can also increase your energy costs, cause your HVAC system to wear down prematurely, and lead to filter failures, allowing dirty air throughout your home.
  • Maintain a constant temperature in your home. Some people adjust their thermostats up/down when they aren’t home. However, that practice can make their HVAC units work unnecessarily hard when they return home. Keep the temperature in your home within a range of four degrees for optimal filter – and HVAC unit – life.
  • Be aware of outdoor air quality. If you live in a climate with all four seasons, you’ll notice shifts in your outdoor air quality with the seasons. Periodic weather episodes, such as high winds during spring, can circulate unusually high amounts of particles in the air, too. Monitor the air outside your home and act accordingly. For example, people living in California during the wildfire season may need to change their air filters more frequently, even if they are not in the immediately impacted area.

Now you understand a bit more about how to select filters of the right MERV rating for your home, how to care for your filter, and ultimately how to ensure clean air for your family. Isn’t it nice knowing that you’ve done all you can to support clean air in your home?

View all posts

Leave a comment