Filters with a MERV rating of 8 or lower are not capable of trapping enough particles to guarantee good air quality, while filters with a rating of 13 or higher are usually not compatible with domestic air conditioning systems. This is because a higher MERV rating often results in lower airflow, which can make the system work harder and use more energy to do its job. The air conditioner has a hot coil on the outside, the condenser, and a cold coil in the air handler on the inside. This cold coil has a specific preferred operating temperature that is based on a certain amount of hot air flowing through that coil and the refrigerant that passes through the copper tube in that coil.
With a higher MERV filter that reduces airflow through this essential part of the air conditioning system, the cold coil can eventually freeze and turn into an ice ball, completely blocking airflow. This can cause more costly problems in the outer capacitor coil. In general, filters with higher MERV indexes capture higher percentages of particles, as well as smaller particles. The MERV-13 is practically where you want to be.
Most modern HVAC systems have no difficulty operating with higher MERV filters, which is why millions of homeowners rely on them. The main risk of high-efficiency air filters is that they remain unchanged for extended periods of time. If you don't mind changing your filters regularly, you're unlikely to have any issues related to the filters in your air conditioning system. Low-efficiency filters are usually within the MERV 1-4 range and high-efficiency filters are the MERV 13 and above.
Filters with higher MERV ratings must be changed more frequently (at least every three months) to avoid airflow restriction, which can cause the system to operate inefficiently or even damage it. A MERV 13 filter is likely to be beneficial if the goal is to prevent droplets from passing through. Keep in mind that as the MERV rating increases, the filter becomes more restrictive and more pressure and energy will be needed to get air through. Not all filters have a MERV nor do all filters have a Merv index of 26%, many of them are available at large stores.
If your home's air conditioning system isn't able to support the MERV 13, opt for a filter with the next highest possible rating. It's best to follow the oven manufacturer's recommendations or consult an HVAC professional to determine precisely what MERV rating is best for your specific system.
