Understanding Air Filter Ratings: FPR vs. MERV vs. MPR — What You Need to Know
When it comes to indoor air quality, not all air filters are created equal. As a homeowner, understanding the differences between air filter rating systems—FPR, MERV, and MPR—can help you make smarter decisions for cleaner, healthier air.
What Are These Ratings?
Let’s break down the three most common air filter rating systems:
1. MERV (Minimum Efficiency Reporting Value)
- Developed by: ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers)
- Scale: 1 to 20
- Purpose: Measures a filter’s ability to capture particles between 0.3 and 10 microns.
- Best For: Industry-standard comparisons across residential, commercial, and industrial applications.
MERV is the most widely recognized and respected rating system. A higher MERV rating means better filtration—but it can also restrict airflow if your HVAC system isn’t designed for it. For most homes, MERV 8–13 is ideal.
🔗 Learn more about MERV from ASHRAE
2. FPR (Filter Performance Rating)
- Developed by: The Home Depot
- Scale: 4 to 10 (color-coded)
- Purpose: Rates filters based on their ability to trap large and small particles, as well as their longevity and weight gain over time.
FPR simplifies the decision-making process with color-coded labels, but it’s a proprietary system, so it’s not directly comparable to MERV or MPR.
3. MPR (Microparticle Performance Rating)
- Developed by: 3M
- Scale: 100 to 2800+
- Purpose: Focuses on capturing particles smaller than 1 micron, such as smoke, bacteria, and allergens.
MPR is great for targeting ultra-fine particles, but like FPR, it’s brand-specific and doesn’t offer a full-spectrum view like MERV.
Which One Should You Choose?
- For Homeowners we recommend to stick with MERV. It’s standardized by the air filtration industry, widely accepted, and backed by ASHRAE research.
Final Thoughts
Understanding these rating systems empowers you to choose the right filter for your needs—balancing air quality, energy efficiency, and system compatibility. When in doubt, consult your HVAC owners manual and refer to trusted sources like ASHRAE.
