These Air Filters Can KILL Your HVAC System! (What Type of Filters Are Best?)
Introduction
Air filters are critical for maintaining indoor air quality and the efficiency of your HVAC system. However, not all filters are created equal. Some filters, often marketed as "high efficiency" or "allergen reduction" solutions, can actually do more harm than good to your heating and cooling system. Let’s dive into why these filters can damage your system and what alternatives are better suited for your home.
Check out this video on YouTube located here
Why Some Air Filters Are Harmful to Your HVAC System
The air filters you see advertised on TV—promising to reduce dust and allergens—may sound like the perfect solution for cleaner air, but they often come with a hidden cost. Most HVAC systems are not designed to handle the increased pressure drop caused by these filters.
Here’s what happens:
Restricted Airflow: High-efficiency filters reduce the amount of air that can flow through your system. While this might improve filtration, it creates a bottleneck that forces your system to work harder.
Frozen Coils: Reduced airflow can cause the air conditioner’s coil to freeze, which disrupts the system’s ability to cool your home effectively.
Heat Exchanger Damage: For furnaces, restricted airflow can lead to overheating, potentially burning out or cracking the heat exchanger. This is not only expensive to repair but also a major safety concern.
Decreased Efficiency: High-efficiency filters can lower the output capacity of your HVAC system, making it less effective at heating or cooling your home.
Understanding Static Pressure: The "Blood Pressure" of Your HVAC System
Think of static pressure in your HVAC system like blood pressure in your body. Just as high blood pressure increases the risk of heart attacks or strokes, high static pressure can lead to system failures.
During an inspection, a static pressure test can measure how much resistance the air filter adds to your system. In one recent case, a homeowner’s system was running 50% over its maximum static pressure capacity due to an allergen-reduction filter. This kind of strain can significantly shorten the lifespan of your system - It's like their system was about to have a heart attack!
The Problem with 1-Inch Filters
Most standard 1-inch air filters, especially those marketed as allergen-reduction or high-efficiency options, are problematic because they lack sufficient surface area to move the amount of airflow needed by the HVAC system. As they attempt to filter out more particles and continue to get dirty, they also reduce airflow, causing the issues mentioned above.
While they may seem convenient and widely available, these filters are often not the best choice for long-term HVAC performance or your wallet.
What Filters Are Best for Your HVAC System?
Instead of 1-inch high-efficiency filters, consider upgrading to a four-inch or five-inch wide media filter rack that accommodates high-surface-area filters. Here’s why:
Better Airflow: Media filters are 4 to 5 inches wide and provide much more surface area for air to flow through. This means more air volume can pass through more easily while still filtering out dust and allergens.
Improved Filtration: The increased surface area captures more particles without compromising airflow nearly as much as one-inch filters do, providing better indoor air quality.
Reduced Wear and Tear: By maintaining proper airflow and reducing static pressure, these filters prevent the strain on your HVAC system that can lead to frozen A-coils in the summer and overheated heat exchangers in the winter. The motor on your blower wheel will work more efficiently and move more air too.
Longer Lifespan: Media filters typically last much longer than 1-inch filters, meaning fewer replacements and less maintenance. Most can last 3-6 months before needing replaced, compared to 1-2 months for regular filters.
Our Recommendation
For most homeowners, we recommend:
Media Filters (MERV 8 to MERV 11): These offer a balance between filtration efficiency and airflow. Higher MERV ratings (13 and above) should only be used with systems designed for them, and make SURE your HVAC tech actually tests the "pressure drop" across these filters after installation!
Professional Installation: Have a professional install a media filter rack if your system doesn’t already have one. This simple upgrade can improve your indoor air quality, save you money on repairs, and save you energy in the long run.
Note that some systems may not have enough space to remove the ductwork and/or equipment needed to install one, so before you waste money on a HVAC tech's trip charge, send them a picture of your HVAC system in advance so they can know if the media rack upgrade is possible or not.
Regular Maintenance: Change your filters as recommended (every 6 months or so for media filters, and every month or two for regular one inch thick filters) and have your HVAC system inspected every year or two, especially if you hear any new noises coming from the system or notice changes in comfort.
Final Thoughts
While high-efficiency 1-inch filters may sound appealing, they can actually harm your HVAC system by restricting airflow and increasing static pressure. Upgrading to a media filter rack with 4- or 5-inch filters is a smarter, more effective solution for cleaner air and a healthier HVAC system.
Have questions or comments about air filters? Leave a comment directly on the YouTube video for the quickest response!
