When it comes to air filters, the Minimum Efficiency Reporting Value (MERV) rating is an important factor to consider. This rating system, established by the American Society of Heating, Refrigeration, and Air Conditioning Engineers (ASHRAE), measures the effectiveness of a filter in trapping dust and other contaminants from passing through. The MERV indices range from 1 to 16, with higher ratings indicating better filtration. MERV 5 filters can capture up to 34% of particles, while MERV 6 filters stop between 35 and 49%.
MERV 7 filters can prevent up to 69% of particles from passing through, and MERV 8 filters trap up to 85%. These filters are slightly more restrictive than the MERV 1-4 filters and have the ability to trap mold spores, pet dander, dust, and pollen. MERV 5-8 filters provide good filtration and remove most pollen, mold spores, and dust mites. At some point, the MERV rating may be too high and cause the central air system to work much harder to push air through the filter. It's important to note that not all HVAC units are compatible with air filters with higher MERV ratings.
A filter with a MERV rating of around 10 to 12 is enough to remove most allergy-causing particles from your home air. High-efficiency particulate air (HEPA) filters trap the smallest particles at a speed even higher than that of the MERV 16 and are generally used in surgical operating rooms, clean rooms, and other contexts that require absolute cleaning. Some air filters, especially those with a higher MERV rating, can prevent air flow due to better air filtration. So which is better: MERV 7 or MERV 8? The answer depends on your needs. If you're looking for a filter that can capture smaller particles such as bacteria, tobacco smoke, car fumes, dust from insecticides, pet dander, and more, then a MERV 13 filter is recommended. However, if you're looking for a filter that can capture larger particles such as pollen and dust mites, then a MERV 7 or 8 filter should suffice. In conclusion, when selecting an air filter for your home or business it's essential to consider the MERV rating.
Higher ratings indicate better filtration but can also cause the system to work harder due to lower airflow. Depending on your needs, you may need a filter with a higher or lower rating. It's best to consult with an HVAC professional before making a decision.