Here are the filtration comparisons between FPR and MERV: FPR 4 -5 is the same as MERV Ratings 6 – 8. FPR 6 – 7 is the same as MERV Ratings 8 - 11.
The FPR ratings and their capabilities are as follows: FPR 4-5 (Green = Good): These filters are able to capture large particles such as dust, dust mites, lint, pollen and dander. FPR 6-7 (Red = Better): These filters are able to capture large particles and small particles such as bacteria and mold spores.
MERV 8 filters equate to an MPR of 600 and an FPR of 5. MERV 10 is equivalent to an MPR of 1000 and FPR of 6. MERV 11 is equal to FPR of 7.
FPR (Filter Performance Rating):
FPR aims to capture both microscopic particles like smoke and bacteria and larger ones like dust and allergies. FPR doesn't measure performance over a wide range of particle sizes and is less thorough than MERV.
For instance, MERV 8 filters catch larger particles and are less restrictive, while MERV 11 filters catch smaller particles and are more restrictive. This means MERV 11 filters not only have higher initial resistance but also build up additional resistance faster as they capture more debris.
For most homes, a MERV rating between 8 and 13 strikes the perfect balance between filtration, airflow, and cost.
While HEPA filters might provide superior filtration, they can often be costly and may require professional installation. MERV 8 filters provide adequate filtration for most households at a reasonable cost. They are easy to replace which makes them a convenient option for many homeowners.
Here are the filtration comparisons between FPR and MERV: FPR 4 -5 is the same as MERV Ratings 6 – 8. FPR 6 – 7 is the same as MERV Ratings 8 - 11. FPR 8 – 9 is the same as MERV Rating 11.
MERV Rating 5-8
Filters in this range will trap anywhere between 20 percent, on the lowest MERV rating of 5, up to 85 percent of particles, at the highest range of MERV 8. Particles that fall into this category include those above as well as fabric protectors, cooing dust, cement dust, hair spray, and mold spores.
FPR Air Filter Ratings
The FPR levels and the particles they can catch include: FPR 4-5 (Good): Dust, link, dust mites, larger pollen particles, and pet dander. FPR 6-7 (Better): All of the above as well as bacteria and mold spores. FPR 8-9 (Best): All of the above plus smoke, smog, and allergens.
In most cases, a MERV 11 air filter isn't too high for residential use. Generally speaking, anything under a MERV 13 air filter should provide very efficient air purification in a home without impacting airflow.
For 1- to 2-inch filters, replace them every 1 to 3 months. For 3- to 4-inch filters, replace them every 6 to 9 months. For 5- to 6-inch filters, replace them every 9 to 12 months.
Filters with MERV ratings between 5 and 8 are often considered medium-quality, which is sufficient for most homes. However, they need to be replaced more frequently than high-quality filters. Filters down to 3 - 10 micron particle size. Controls contaminants such as mold, dust lint, cement dust, and textile fibers.
Thick air filters may intuitively seem better, for the reasons listed above. Thicker usually means more air filtration. Thicker air filters tend to last longer because they have more surface area in which to capture and hold air particles.
What kind of filter should I use in my home HVAC system to help protect my family from COVID-19? Minimum Efficiency Reporting Values, or MERV, reports a filter's ability to capture particles. Filters with MERV-13 or higher ratings can trap smaller particles, including viruses.
FPR scores filter from one to ten, with ten being the best.
A higher air filter MERV rating means it traps smaller particles, even microscopic bacteria and viruses, but it also restricts airflow and requires proper ductwork in order for your equipment to operate properly.
Good filtration: MPR 300 to 700
If you're looking for general air filtration, selecting a Filtrete™ Air Filter with an MPR of 300 to 700 can be sufficient.
Suitable for Most Homes: MERV 8 filters are effective at capturing larger particles like dust, pollen, and pet dander. For many homes, especially those without specific indoor air quality concerns, MERV 8 filters strike a good balance between filtration and airflow.
MERV Rating 8-13
These filters are typically the right choice for use in homes and many businesses.
A MERV 8 filter is going to reduce a majority of pollutants but does not catch the smaller pollutants and allergens that could circulate in your air. It is recommended that this kind of filter be replaced every 90 days.
MERV rating 5-8
Filters in the 5-8 MERV value range are also able to trap particles with 3.0-10.0 microns in size, but they are more efficient in doing so. A MERV 5 filter will trap up to 34%, MERV 6 will stop 35-49%, MERV 7 will prevent up to 69%, and MERV 8 will catch up to 85% of particles.
ASHRAE currently recommends using a minimum MERV 13 filter, which is at least 85% efficient at capturing particles in 1 µm to 3 µm size range. A MERV 14 filter is at least 90% efficient at capturing those same particles.
These high-quality filters trap particles as small as one micron, including Legionella and humidifier dust. MERV 9 to 12 filters are the best filters that a residential HVAC system will accommodate without serious system modifications.