How to Choose the Right Air Filter for your Home

Adulting comes with some daunting tasks. Changing air filters is one of them. It’s not so much changing them that’s hard, but how do you choose the right one? What’s a MERV rating? Do their fancy names and promises to reduce allergens, pet dander and bacteria actually matter? How do you choose?  Air filters perform an important task in your home and can be expensive, so it’s important to get the right one. The air filter in your home HVAC unit is a critical component of the whole system and greatly affects your unit’s performance. Not only do they play a big role in indoor comfort, but they also have a major impact on HVAC equipment. Here is what you need to know about selecting the right filter to best fit your needs.

Why do I need an air filter? 

The HVAC system “sucks” in air where it is conditioned and then used again. During this process, air is forced through the air filter. The filter traps particulates and contaminants, removing them from the air. These particles are now no longer able to be recirculated into the air you breathe. Types of contaminants that air filters trap:

  • Dust mites
  • Debris
  • Mold spores
  • Pet dander
  • Smoke
  • Bacteria
  • Dust
  • Pollen
  • And more

Not only do they keep your air cleaner, but they also keep the coils and heat exchanges on the heating and air conditioning system clean. This prolongs the life of your HVAC equipment. Air filter investments cost a lot less than HVAC repairs!  If it’s been a while since you’ve changed your filter, you’ll see this proof in how dirty it is. Yuck. Now that you know the “why”, let’s talk about what to buy.

First things first

Check the size you need. The size should be printed on your current filters. They come in a number of sizes so it’s important you get the correct one to fit your air return. 

Air filter ratings

Yes, they matter, and no they don’t have to be confusing. Here are the most common rating systems you’ll see. 

MERV rating: The Minimum Efficiency Reporting Value (MERV) was designed by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) and known as the primary rating system for air filtration. On a scale of 1 to 16, the MERV determines how effectively a filter traps the contaminants that you don’t want circulating in your home.

  • MERV 1-4: Dust, dust mites, pollen, textile fibers and insects
  • MERV 5-8: Finer dust, mold spores, pet dander, hair spray and fabric protectors.
  • MERV 9-12: Car emissions, lead dust, legionella and other bacteria.
  • MERV 13-16: Larger bacteria, oil droplets and dust from smoke.

FPR rating: The Filter Performance Rating (FPR) was founded by the Home Depot and specifically applies to air filter brands sold in Home Depot stores. This uses a a ranking of 4-10 that rates a filters effectiveness.

  • FPR 4-5 (Good): Dust, link, dust mites, larger pollen particles and pet dander.
  • FPR 6-7 (Better): All of the above as well as bacteria and mold spores.
  • FPR 8-9 (Best): All of the above plus smoke, smog and allergens.
  • FPR 10 (Premium): All of the above and odor causing particles.

MRR rating: The Microparticle Performance Rating (MPR) was developed by a manufacturer called 3M. The MPR rates the ability of filters to capture airborne particles that are smaller than 1 micron. Its ratings typically range from 300 to 2800. They’re based on the size of the pollutants that can be filtered. 

  • MPR 300: Dust, pollen, and lint.
  • MPR 600: All of the above plus dust mites and mold spores.
  • MPR 1000-1200: All of the above as well as smoke, smog, cough and sneezes.
  • MPR 1500-2800: All of the above in addition to bacteria and some viruses.
choose an air filter

What’s right for you?

As with most things there are lower-end, mid-level and high-end choices available to purchase. Since air filters range in quality, they won’t clean your air with the same efficiency. The higher the quality, the more contaminants that will be removed from your indoor air. And of course, higher quality will likely mean a higher cost.

Filters with a MERV rating of 11 or better are usually recommended for the average home. Things to consider when choosing yours:

  • Do you suffer from allergies? 
  • Do you have pets?
  • Do you suffer from asthma?
  • Are you experiencing significant air pollution? (Northern CA summers!)
  • Have you recently completed a significant home remodel? 

The more “yes” answers, the higher rating you will benefit from, but hold on…

Bigger isn’t always better

The higher the rating the easier a filter can become clogged and interfere with the airflow of your system by restricting it. This reduces the effectiveness of your heating and cooling systems and can even result in damage to the HVAC equipment. Make sure that your HVAC system can handle the filter you choose and be sure to change regularly as recommended.

Why do I have to change them so often?

Since a dirty air filter can clog your HVAC system and reduce airflow it’s important to check them every month. If they’re dirty, change them. At the very least, change the filters every three months. Regular changing will help ensure that you don’t restrict airflow to the HVAC system. If the airflow is restricted, the HVAC system can malfunction and cause equipment damage. The reduced airflow inside the HVAC system makes the fans work harder and wear out quicker.

If the HVAC equipment has to work harder, you increase your home’s energy usage and your monthly electric bill payments.

Do they make reusable air filters?

I’m so glad you asked! We offer customers the Electromaze filters as a washable, reusable option. You can read about them at and our technicians can install them for you. Just ask when you make your appointment so we can be sure we have your size!

electromaze air filter
The Electromaze© Air Filter

Now you should feel confident in buying the right air filters for your home. The correct filters and changing them as recommended will help your home’s air quality and help extend the life of your HVAC. Still have questions? We’d love to help! Give us a call at 916-224-7159.

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