When it comes to air filters, the MERV rating system is used to measure resistance. In a nutshell, the higher the MERV rating, the more effective the filter will be. However, using an air filter with a MERV rating that is too high can be just as bad as using one that is too low. Air filters with higher MERV values may filter more, but the thickness of the filter material can restrict air flow.
This can lead to decreased comfort, increased energy use, and accelerated wear and tear on HVAC components. In particular, using an air filter with a MERV rating that is too high can damage the compressor, heat exchanger and air conditioner coil. When selecting the right filter for your application, it's important to remember that higher isn't always better. Using an air filter with a MERV rating higher than recommended by the boiler or air conditioner manufacturer may affect its performance.