As a seasoned HVAC professional with over 40 years of experience, I have witnessed the impact of using highly restrictive high MERV filters in HVAC systems. While these filters may seem like a logical choice for improving indoor air quality, they can actually do more harm than good by limiting airflow and putting strain on the system. First, let's define what a MERV rating is. MERV stands for Minimum Efficiency Reporting Value and it measures the effectiveness of an air filter in capturing particles. The higher the MERV rating, the smaller the particles it can capture and the higher the percentage of particles it can remove from the air.
However, this also means that the filter becomes more restrictive, which can lead to decreased airflow. Low-efficiency filters typically have a MERV rating of 1-4, while high-efficiency filters are rated at MERV 13 and above. It's important to note that the MERV scale is not linear, meaning that the difference between a MERV 6 and a MERV 8 is almost double in terms of particle capture percentage. As the MERV rating increases, so does the pressure and energy needed to expel air through the filter. So why is restricted airflow a problem for HVAC systems? Simply put, these systems need sufficient airflow to work efficiently and last longer. When airflow is restricted, it puts strain on the system and can lead to breakdowns or even complete system failure. One common misconception is that using a high MERV filter will automatically improve indoor air quality.
While it may capture more particles, it can also cause issues with airflow and put strain on the system. Additionally, some homeowners may opt for N95+ filters, thinking that they are the best option for improving air quality. However, it's important to note that the N95+ rating not only refers to the filter material, but also the front seal that it creates. Another factor to consider is the frequency of filter changes. High-efficiency filters may not need to be changed as often as low-efficiency ones, but this can also lead to problems.
Over time, these filters can become clogged with captured particles, further restricting airflow and putting strain on the system. It's important for homeowners to consult with an HVAC professional before using any type of filter in their system. One way to improve airflow while still using pleated and high MERV filters is to install a 5-6 inch media filter. These filters have more surface area for air to pass through, which can improve airflow and reduce strain on the system. However, it's crucial to have a professional install these filters to ensure they are compatible with your system. In conclusion, while high MERV filters may seem like a good idea for improving indoor air quality, they can actually cause more harm than good by restricting airflow and putting strain on HVAC systems.
It's important for homeowners to consult with an HVAC professional before using any type of filter and to regularly change filters according to manufacturer recommendations. By finding the right balance between air quality and airflow, you can ensure your HVAC system works efficiently and lasts longer.