A higher MERV rating can have an effect on airflow, but it is not necessarily a problem. Most modern HVAC systems are designed to work with higher MERV filters, and the main risk of using them comes from not changing the filter often enough. The MERV rating is a measure of the filter's effectiveness in trapping particles, and a higher rating means fewer particles will pass through the filter. This can lead to improved indoor air quality, reduced energy use, and better performance from your HVAC system.
However, using an air filter with a MERV rating that is too high can restrict airflow and cause damage to the compressor, heat exchanger, and air conditioner coil. Studies have shown that airflow decreases as the MERV rating increases. In two HVAC systems, the high MERV filters decreased airflow by 7% and 11%, while the medium MERV filters decreased airflow by 3% and 8%. It is important to note that using an air filter with a MERV rating that is too low can also be detrimental to your HVAC system.
When choosing between a MERV 8 air filter and a MERV 11 air filter, it is important to consider the size of the filter and the type of fan motor in your HVAC system. On average, it is recommended that most homes and commercial spaces have a filter with a MERV rating of at least 5 to 12 in the high-end. A MERV 14 rating or higher is designed for commercial HVAC systems that can handle the coarsest filter material. In general, it is important to keep abreast of changing filters and replace dirty filters often enough to ensure optimal performance from your HVAC system.
There is no price for peace of mind, so if you feel that a high MERV filter would provide it, you should go ahead with the caveat that you should replace dirty filters often enough.