When researching HVAC systems, airflow is an important factor to consider. A higher MERV rating means greater resistance, which in turn reduces airflow. However, there are other factors to consider, such as the size of the filter and the type of fan motor in your HVAC system. Research shows that in general, HVAC systems with high MERV* filters have a higher pressure drop across the entire filter.
A MERV rating is a good indication of the effectiveness of an air filter in your central split HVAC system. The higher the rating, the better the filter. As the MERV rating increases, fewer and fewer contaminants and dust pass through the filter, making the incoming airflow of better quality. The higher the MERV rating, the less airflow there will be.
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 ratings can filter more, but the thickness of the filter material can restrict airflow. This can decrease comfort, increase energy use, and accelerate wear and tear on HVAC components. In particular, using an air cleaner with a MERV rating that is too high can damage the compressor, heat exchanger, and air conditioner coil. When it comes to air filters, every system, every home, and every person's air quality requirements will be unique.
It is a standardized system created by the American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE) and used by all manufacturers of air filters. Choosing the right MERV rating is an important decision in terms of total cost, air quality, and product durability. A MERV rating is to ensure that incoming ventilated air meets area-specific air quality standards. On average, it is recommended that most homes and general commercial spaces have a filter with a MERV rating of at least 5 to 12 in the high-end. Making sure that you replace your air filter as directed by the manufacturer will help ensure that you get the most out of your HVAC system while maintaining good air quality.