When it comes to air quality, higher MERV ratings are often seen as the most effective option. However, it's important to remember that higher ratings also mean greater resistance, which can lead to decreased airflow. Low-efficiency filters are usually within the MERV 1-4 range, while high-efficiency filters are MERV 13 and above. The MERV scale is not linear; the difference between a MERV 6 and a MERV 8 is almost double in terms of the percentage of particles captured.
Using an air filter with a MERV rating that is too high can be just as bad as using one that is too low. This is because the thickness of the filter material can restrict airflow, leading to decreased comfort, increased energy use, and accelerated wear and tear on HVAC components. It's important to keep in mind that as the MERV rating increases, the filter becomes more restrictive and more pressure and energy will be needed to propel the air. When researching HVAC systems, airflow should be taken into account.
The higher the filter rating, the smaller the particles it will capture and the higher the percentage of particles captured. However, there are many other factors at play, such as the size of the filter and the type of fan motor in your HVAC system. In general, filters with higher MERV ratings capture higher percentages of particles, as well as smaller particles. MERV-13 is generally considered to be a good balance between efficiency and airflow.
Ultimately, it's up to you to decide what kind of filter you want to use; if you feel that a high merv filter would provide peace of mind, then go for it. Just make sure to replace dirty filters often enough - which can be a week or two depending on the MERV rating, effective area of the filter, and amount of particles entering your home. The MERV rating is important because it helps you understand how effective an air filter is at filtering particles of certain sizes. For example, if you have someone in your household who suffers from allergies, you may want a higher MERV rating. A MERV 8 carbon filter will provide more than enough filtering of dust and allergens and will filter dozens of toxic gases that will pass directly through a MERV 13 filter. When buying air filters for a new HVAC system, always keep in mind the MERV rating.
Increasing a filter to a higher MERV can increase the delta P across the filter - but this should be weighed against any reduction in airflow caused by a high MERV filter. Technology for HVAC units has progressed since then, and most modern units in recent years should be able to have a MERV 8 filter at least. This comparison table helps highlight the differences between the MERV 8 and MERV 11 filters to make it easier to decide which one works best for your particular needs. If you're concerned about outdoor air pollution, family members with respiratory problems, or pets in the house, then a higher MERV rating might be a good idea. A MERV 11 air filter can filter a large percentage of fine particles that a MERV 8 air filter cannot.