Do I Need an Additional Air Purifier with My Existing HVAC System?

Learn about how important it is to consider your HVAC system's MERV rating when choosing an additional air purifier for your home. Understand how different ratings affect your system's efficiency and how often you should change your filter.

Do I Need an Additional Air Purifier with My Existing HVAC System?

When it comes to air filtration, the MERV rating is an essential factor to consider. This rating system helps you decide the efficiency of the filter when it comes to capturing particles of certain sizes. It's important to note that using an air filter with a MERV rating that is too high can be just as bad as using one that is too low. This is because the thickness of the filter material can restrict airflow, leading to reduced comfort, increased energy use, and accelerated wear and tear of air conditioning 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.

It's important to understand the differences between the MERV and the MPR & FPR in order to choose the filter that best suits your needs.


air filters can filter a large percentage of fine particles, but a MERV 8 air filter cannot. However, a high MERV rating on an air filter usually means that the filter is thicker and the air conditioning system will have to work harder to get air around the house. Filters with higher MERV ratings should be changed more frequently (at least every three months) to avoid restricted airflow that can cause the system to operate inefficiently or even damage it. It's also worth noting that filters at the lower end of the MERV scale are not even tested to verify their effectiveness in capturing E1 and E2 particles.

E1, E2, and E3 particles are particle sizes used to test air filters to determine the MERV classification. MERV 8 air filters are almost as affordable as the least efficient products, so they offer good value for money. The same is true for homes with smokers or pets, since MERV 11 air filters better eliminate odors. Considering the threat posed by COVID-19 and other germs, replacing a building's air filter with a HEPA one is a much more effective measure than simply a MERV 13, considering the small size of the virus (from 0.06 to 0.12 microns); the more efficient the filter, the better. In these cases, a MERV 11 air filter can provide additional benefits and capture a wider range of particles that would pass through a MERV 8 filter. Since the MERV classification system is standard, it makes it easier to compare filters with different MERV ratings.

If your home's air conditioning system is not compatible with the MERV 13, opt for a filter with the next highest possible rating. One thing to keep in mind is that not all HVAC units can accommodate air filters with higher MERV ratings. Based on these characteristics, a MERV 8 is considered to have higher filtration compared to air filters with a lower MERV rating.