If you want at least your air to be cleaned and handle dust, mold, pollen and bacteria, then a Merv 8 will do the job. Typically, a filter with a higher merv rating will reduce airflow. However, there are many other factors at play, such as the size of the filter and the type of fan motor of the HVAC system. A higher MERV rating means greater resistance, which means less airflow.
When researching HVAC systems, airflow will increase a lot. This is because it is very important to the performance and longevity of your oven or your air handler. Airflow is also the key to a comfortable home. Using an air filter with a MERV rating that is too high is as bad as using one that is too low.
Air filters with higher merv ratings may filter more, but the thickness of the filter material may restrict airflow. Restricted airflow can decrease comfort, increase energy use, and accelerate wear of HVAC components. In particular, using an air filter with a too high MERV rating can damage the compressor, heat exchanger, and air conditioner coil. A MERV rating is a good indicator of the effectiveness of an air filter in your central HVAC split system.
The higher the rating, the better the filter. As the MERV rating increases, fewer and fewer pollutants and dust pass through the filter, making the incoming airflow of better quality. As you can see above, research shows that overall, HVAC systems with high MERV* filters have a higher pressure drop across the filter. This part is common to the three previous studies.
The AC coil inside or near your furnace or air handler gets very cold as it draws heat out of the space and pumps it out. A normal flow of warm air over the coil will prevent its surface from falling below 32°F. Low airflow allows coil to freeze cool. Then the moisture in the air freezes and the coil is covered with ice.
At that time, the air conditioning system can't do its job. The goal of using a MERV 12 filter or higher is a better IAQ: cleaner, more breathable air for everyone, and especially for those with allergies, asthma, COPD, etc. If you are in a situation where you should not use a high MERV (12+) filter for your oven or air conditioner and would like to research air purifiers, here are two suggestions. For example, general filtration with an 8 MERV will filter up to about 10 microns, while a 13 merv filter will only have about 0.3 microns in pitch.
On average, it is recommended that most homes and retail spaces in general have a filter with a MERV rating of at least 5 to 12 in the high-end. As the filter becomes dirty and more airflow is restricted, the PSC motor will provide even less airflow. Many people don't consider how a filter with a high MERV rating will affect other parts of the HVAC system. Meanwhile, air filters with a MERV rating of 14 or higher are designed for commercial HVAC systems that can handle the coarsest filter material.
The same goes for households with smokers or pets, as Merv 11 air filters are better at eliminating odors. Through this site and the trails that led me, I have learned that two MERV 11 filters can have the same filtering capacity, but one could allow more air to be transferred. MERV 8 air filters are almost as affordable as less efficient products, making them good value for money. Based on the characteristics mentioned above, a MERV 8 is considered superior filtration compared to air filters with a lower MERV rating.
Raising just three levels of MERV rating can be a smart move that makes air cleaner or a detrimental option for the entire HVAC system when considering the MERV 8 vs. MERV 11 airflow capabilities. However, if you are concerned about outdoor air pollution, family members with respiratory problems, or pets are in the house, then it would be a good idea to go for a higher MERV rating. .