The quality of an air filter is evaluated by its classification, which indicates the filter's ability to block out particles in the air. The higher the rating (for MERV, FPR and MPR), the smaller the air and dust particles your home air conditioner filter can capture. When it comes to effectiveness, it's difficult to choose between a MERV rating or an FPR rating. Both are useful, but the FPR may be easier to understand, since it uses a more intuitive numbering system. FPR scores are filtered from one to ten, with ten being the best.
In addition, filters with an FPR rating of 4 to 5 will not restrict air flow as much as filters with higher FPR ratings. This means that your HVAC system will operate more efficiently and you'll spend less money on your utility bills. A more efficient filter will be more effective in removing particles from the air as they enter the HVAC system. They will also improve the air quality in your home and keep your lungs happy. Since the filtration is more complete, your HVAC unit will need more energy and effort to use them.
The amount may vary depending on the home and the HVAC system, but with modern technology, the increase in airflow resistance that comes with a high-efficiency filter is often marginal. This is important to keep in mind, as many homeowners believe that the relationship is simply linear, that is, as filtration efficiency increases, so does resistance to air flow at the same rate. However, this is not accurate and is the reason why millions of homeowners use high-efficiency filters without worry. For example, the Second Nature's Essential filter is approximately 450% more effective at capturing particles than an inexpensive, low-efficiency fiberglass filter, but its resistance to airflow is only 20% higher, a marginal difference. This means that by using this type of air conditioning filter, you can prevent viruses and bacteria from entering your space.
Ironically, the effectiveness of low-efficiency air filters increases as the filter is filled with dirt and dust. If someone in your family has an allergy or asthma problem, you should use this type of air conditioning filter. Like the MERV classification system, the higher the rating, the more efficient the air filter is at blocking small particles. The MERV filter classification is the national and international industry standard classification system established by the American Society of Heating, Refrigeration and Air Conditioning Engineers. Air filters with an FPR rating of 4 to 5 will provide a basic level of air filtration that is sufficient for most homes. MERV filters 9 to 12 provide excellent filtration for homeowners, but can be expensive if you need to change them frequently.
This is because there are different standards to meet, so you'll see some air filters with a MERV rating, while others appear as MPR or FPR. MERV 13 air filters even provide additional filtration power against fine particles compared to MERV 11 filters. On average, you should change your air filter every 30 days if it's made of fiberglass or if it's considered a “cheap” filter with a low rating. The higher the MPR value, the better the filter medium is to capture indoor air pollutants smaller than 1 micron in diameter. As it passes through the system and through the filter, the air filter traps particles and dust before they enter the house.
When these filters become dirty and need to be replaced, air can continue to flow through them and not become clogged as easily. However, older units may not be able to withstand sufficient air pressure to force air through a larger filter. In my opinion, I believe that FPR system is a more complete classification system for air filters compared to MERV and MPR systems. It provides a better understanding of how efficient an air filter can be at blocking out small particles while still allowing for adequate airflow through your HVAC system. If you're looking for an effective way to improve your home's indoor air quality without sacrificing energy efficiency or increasing your utility bills too much, then investing in a high-efficiency FPR rated filter may be worth considering.
