A MERV rating is a great way to measure the effectiveness of an air filter in a split central HVAC system. As the MERV rating increases, fewer and fewer contaminants and dust pass through the filter, improving the quality of the incoming air flow. Research shows that, in general, HVAC systems with high MERV filters have a greater pressure drop in the filter. This can lead to a 7-11% reduction in airflow compared to low-MERV filters.
It's important to select the right MERV rating for your space. Low-efficiency filters are generally found within the MERV 1-4 range, while high-efficiency filters are MERV 13 and higher. For example, general filtration with a MERV 8 will filter down to approximately 10 microns, while a MERV 13 filter will only have about 0.3 microns in pass. Filters with higher MERV ratings must be changed more frequently (at least every three months) to prevent restricted airflow from causing the system to operate inefficiently or even damage it.
Most modern HVAC units should be able to equip at least one MERV 8 filter, but it's best to follow the oven manufacturer's recommendations or consult an HVAC professional to determine exactly which MERV rating is best for your specific system. If you own pets, you may need a higher rating such as a MERV 10 or 13 to control their dander, which tends to have smaller particles than the contaminants discussed above. The analysis of the filter area and pressure drop illustrates how HVAC experts are considering all parameters that can be adjusted, without bringing costs to unacceptable levels. The direction that would protect most people is maximum airflow and, at the same time, being able to use a MERV 13 or higher filter. If your home's air conditioning system isn't capable of supporting the MERV 13, opt for a filter with the next highest possible rating. In conclusion, higher MERV ratings can affect airflow in an HVAC system by reducing it by 7-11%.
It's important to choose the right MERV rating for your space and consult an HVAC professional if necessary. Most modern HVAC units should be able to equip at least one MERV 8 filter, but if you own pets you may need a higher rating such as a MERV 10 or 13.