As an expert in the field of HVAC systems and air filtration, I have encountered numerous misconceptions and myths surrounding the use of high MERV filters. Many homeowners are under the impression that using a filter with a high MERV rating is always better, but this is not necessarily the case. In fact, using a filter with a MERV rating that is too high can have negative consequences on your HVAC system and indoor air quality. Let's start by understanding what a MERV rating actually means.
MERV
stands for Minimum Efficiency Reporting Value and it is a scale that rates the effectiveness of air filters in removing particles from the air.The higher the MERV rating, the more efficient the filter is at capturing particles. However, this also means that the filter material is thicker and can restrict airflow, which can lead to problems in your HVAC system. While high MERV filters may be able to filter more particles from the air, they also have greater resistance. This means that your HVAC system has to work harder to push air through the filter, which can result in decreased efficiency and increased energy consumption. In extreme cases, this can even lead to damage to your HVAC system. But before you start worrying about the potential downsides of using high MERV filters, it's important to note that most modern HVAC systems are designed to work with these types of filters.
In fact, millions of homeowners rely on high MERV filters for their air filtration needs. The key is to make sure that you are regularly changing your filters. If you are diligent about changing your filters on a regular basis, then you are unlikely to experience any problems related to using high MERV filters. However, if you neglect to change your filters for extended periods of time, then you may run into issues. This is because high-efficiency filters are not designed to be used for long periods of time without replacement. So, what exactly is considered a high MERV filter? Generally, filters with a MERV rating of 13 and higher are considered high-efficiency.
For reference, a MERV 16 filter is able to filter out 95% of particles from the air. In fact, there are even tutorials on YouTube that show how to make your own N95 mask using a MERV 16 filter. It's important to note that the MERV scale is not linear, meaning that the difference between a MERV 6 and a MERV 8 filter is much greater than the difference in percentage of particles captured. Now, let's address some common concerns about using high MERV filters. One concern is that washing these filters with alcohol can create dangerous chemicals.
While this may be true if you are washing filters made of certain materials, such as fiberglass, it is not an issue with most high MERV filters. However, it's always best to err on the side of caution and use sunlight to disinfect your filters instead. Another concern is that using activated carbon filters with a high MERV rating can release unwanted chemicals into the air. This can be avoided by degassing the filter before use. A MERV 8 carbon filter is more than sufficient for filtering dust and allergens, as well as dozens of toxic gases that can pass through a MERV 13 filter. It's also worth noting that not all particles are created equal.
For example, a MERV 11 filter only needs to stop 20% of particles from 0.3 to 1.0 microns in size, which are three to ten times larger than a COVID-19 particle. A MERV 12 filter only needs to stop 35% of particles smaller than 0.3 microns, and a MERV 13 filter only needs to stop half. So, if your main concern is preventing droplets from passing through, a MERV 13 filter should suffice. It's also important to clarify that both surgeries and HVAC systems use MERV filters, but they do not use fiberglass filters. Additionally, a 1-inch thick MERV 12 filter is likely to be more restrictive than a 4-inch thick MERV 12 filter.
Ultimately, the most important factor is peace of mind. If using a high MERV filter gives you peace of mind, then go for it. Just make sure to replace dirty filters regularly, which may mean every week or two depending on the MERV rating and the amount of particles in your home.