The MERV rating, or Nominal Minimum Efficiency Value, is a nationally recognized measurement system used to evaluate air filters. It is based on the filter's ability to trap particles of a certain size, ranging from 0.3 to 10 microns (µm).When selecting the right MERV rating for your air filter, you must consider the capabilities of your air conditioning system and the indoor air quality you want. In general, filters with a MERV rating of 16 or lower are suitable for residential, commercial and general hospital use. If your family has allergies or respiratory problems such as asthma, you may want to invest in filters with a higher MERV index. It is important to check if your air conditioning system has a maximum MERV rating before buying a new heating filter.
Exceptionally powerful HVAC fans are needed to effectively push air through filters that are at the higher end of the MERV rating scale. Finding filters with the right MERV ratings is essential to ensure that air is well filtered without overloading the HVAC system. For example, a higher MERV rating doesn't always mean that a filter is the best choice for your boiler. Filters with higher MERV ratings usually have a denser filter material, which means that more force is needed to push air through the filter. As the MERV index increases, airflow decreases, forcing the HVAC system to work harder to move air through the boiler, increasing the chance of possible breakdown. In residential air conditioning systems, filters in the order of 1 to 4 are most common, but it is not uncommon for homeowners to use filters with MERV ratings of up to 8 in typical household systems.
If you have one, be sure to buy a heating filter with a MERV rating lower than the system's maximum. All air filters require periodic cleaning and replacement in order to work properly. It is important to follow the manufacturer's recommendations for maintenance and filter replacement.