How well your central heating and cooling system cleans the air largely depends on the quality of your air conditioner filters.

    Filters are rated from 1 to 16 on the Minimum Efficiency Reporting Value (MERV) scale. The MERV scale measures the percentage of particles between 0.3 to 10 microns that a filter captures. The higher the MERV number, the better the filter is at trapping small particles.

    The Microparticle Performance Rating (MPR) measures particles between 0.3 and 1 microns. MPR ratings range from 0-2200, with higher numbers indicating better filtration of tiny particles. Mold spores and pollen particles are usually 10-30 microns. Bacteria particles are two to three microns, while tobacco smoke particles are around 0.5 microns.

    Keep reading for an overview of the MERV scale and how to choose the best air conditioner filter for your home. 


    Understanding the MERV Scale

    When picking an air conditioner filter, keep these MERV guidelines in mind:

    • MERV 1-4: Cheap fiberglass mesh filters only catch particles over 10 microns. These filters won’t do much to clean the air in your home.
    • MERV 5-8: These medium pleated filters trap particles down to 3.0 microns. Good for basic filtration.
    • MERV 9-12: High-quality pleated filters that filter out particles as small as 1.0 microns. Look for a filter with at least this standard for reducing allergens.
    • MERV 13-16: The highest standard for filters. They filter tiny particles down to 0.3 microns.
    • MERV 17-20: Also called HEPA filters, they remove 99.97% of particles 0.3 microns and larger, but they may be too dense for your HVAC system.
    Today’s Homeowner Tips

    Check your HVAC system manual for recommended filtration levels to pick the right MERV rating. High MERV filters can overload systems not designed for them.


    Other Ways to Reduce Allergens

    Along with using quality filters and changing them regularly, you can try additional ways to reduce allergens in your home. One option is to limit carpets and rugs, which harbor allergens. Hard floors are easier to clean.

    If you have pets, keep them outdoors as much as possible to reduce dander inside. Zero-VOC paints and furniture will decrease indoor air pollution. It’s also a good idea to vacuum with HEPA filter models that trap allergens.

    To improve air quality, install room air purifiers with HEPA filters, which filter air continuously. Houseplants like philodendrons, peace lilies, and snake plants will naturally purify the air.


    Maintenance Is Key for Air Filter Performance

    You need to replace air filters regularly for the best performance. Check them at least every three months. 

    There are several signs indicating it may be time to replace your HVAC filter. Increased energy bills resulting from your system working harder to push air through a clogged filter is one red flag. Reduced airflow from your home’s vents is another telltale sign a filter change is needed. You may also notice more dust buildup on vents and other indoor surfaces if your filter is not trapping particles effectively. 

    Finally, stuffiness, allergies, or illness among people in your household can signal your filter needs swapping. If you notice any of these issues, it’s a good idea to inspect your filter and consider replacing it with a fresh one.

    Follow the manufacturer’s guidelines for replacing disposable pleated filters. For washable, reusable filters, gently vacuum or wash them. Let them fully dry before putting them back in.

    Today’s Homeowner Tips

    When installing a new filter, carefully place it to prevent air leaks around the edges. Confirm the airflow arrow points in the right direction.


    Improving Your HVAC System

    Upgrading your HVAC system can boost air filtration in your home, but proper sizing and installation are crucial. Talk to an HVAC pro about these add-on upgrades:

    • Media air cleaner: A pleated filter coated to better capture particles. Typically, $500 to $1,000 with installment costs.
    • Electronic air cleaner: Electrically charged plates that pull in and trap particles with an estimated price of $800 to $3,500 installed.
    • UV light system: UV bulbs kill mold, bacteria, and viruses passing through. Usually, $500 to $800 installed.
    • Hybrid humidifier: Humidifies and filters air. Models with fans improve circulation. $400 to $700 installed.

    Shop Smart for Air Conditioner Filters

    To pick the right air conditioner filters at the best price, measure your current filter to get the right replacement size. Then, find the ideal MERV rating for your HVAC system’s capabilities.

    Buy filters in bulk packs online to save up to 40%. Often, you can sign up for auto-shipments so you never forget to swap them out. I recommend opting for antimicrobial treatments to inhibit mold growth.

    Check the MPR rating to filter tiny particles — the higher, the better. For reusable filters, pick washable metal or plastic over disposable. Be sure to compare prices across brands for the best deal based on performance needs.


    So, Is It Worth Investing in Premium HVAC Filters?

    Upgrading to a higher efficiency MERV filter offers clear indoor air quality benefits. Advanced filters trap more dust, allergens, and pollutants. This leads to cleaner, healthier air in your home.

    While premium filters cost more up-front, they save money long-term through improved energy efficiency and less duct cleaning needed. Few easy home upgrades can make as big an impact on your indoor air.

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    FAQs About Air Conditioner Filters

    How often do I need to change air filters?

    Experts recommend swapping filters about every three months. Check them more often if you have pets or allergies.


    Where does the air filter go?

    Air filters belong in the return duct just before air enters your HVAC system. Check the filter housing for an airflow direction arrow.


    Can I clean and reuse air filters?

    It depends on the type of air filter. Washable, reusable pleated filters can be vacuumed out and washed. However, disposable filters need to be replaced.


    What if I don't change the filter enough?

    Dirty filters make your HVAC system work too hard, waste energy, and blow more dust inside your home. They can also lead to mold in the HVAC system.


    Are pricier air filters worth the cost?

    Higher-efficiency filters do a better job of cleaning the air. The long-term benefits are worth the small extra up-front cost.



    *Costs are sourced from HomeGuide, Home Advisor, and HVAC.com estimates.

    Editorial Contributors
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    Elise LaChapelle

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    Elise LaChapelle is a copywriter with over a decade's experience in the digital space. She specializes in blogging, website content, social media, and e-mail marketing across a diverse array of clients, helping them to connect with their target audience through concise, compelling messaging. When she's not crafting copy, Elise enjoys working out, cooking, and spending time with her husband and two daughters.

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    Amy DeYoung

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    Amy DeYoung has a passion for educating and motivating homeowners to improve their lives through home improvement projects and preventative measures. She is a content writer and editor specializing in pest control, moving, window, and lawn/gardening content for Today’s Homeowner. Amy utilizes her own experience within the pest control and real estate industry to educate readers. She studied business, communications, and writing at Arizona State University.

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