MERV 11 furnace filters have a particle retention rate of just over 90%, while MERV 13 air conditioning filters have a particle retention rate of around 98%. This makes the latter significantly more efficient. The main difference between the two is that MERV 13 filters are better at trapping fine particles. They can capture 50% of particles that are 0.3 to 1.0 microns in size, compared to MERV 11 filters which can only capture 20%.
This means that MERV 13 filters can filter out bacteria, viruses, smoke, and microscopic allergens. MERV 13 filters provide greater filtering power against fine particles than MERV 11 filters, making them ideal for heavily contaminated areas, areas affected by wildfires, or to help prevent the spread of diseases. However, they come with a higher price tag and increased resistance to airflow. Unless you have people over 65 years of age, under 5 years of age, or people with a weakened immune system in your home, you don't need to invest in a MERV 13 filter.According to the EPA, MERV 13 filters are 90% efficient when capturing particles between 3.0 and 10 microns, an efficiency of 85% when capturing particles between 1.0 and 3.0 microns, and an efficiency of 50% when capturing particles between 0.3 and 1.0 microns.
The COVID-19 virus is 0.1 microns in size, which is too small for MERV 13 filters to catch. In most homes and commercial buildings, filters with a MERV rating between 8 and 13 will be sufficient for filtering the air. Filters with a MERV rating greater than 13 are tightly interlocked to capture potentially harmful contaminants. It's best to use a category 13 MERV filter to protect yourself from the bacteria that spread the virus, but you should also consider adding air quality solutions to your home if you live in densely populated areas with high levels of air pollution, or if you have immunosuppressed people or people with severe allergies and asthma.
