Summary
Minimum Efficiency Reporting Values, also known as MERV, is a method commonly used to classify the effectiveness of air filters that was developed by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE). MERV filters are integrated into HVAC systems to clean particulate matter, fumes, and germs out of outdoor or recirculated air before entering the building. Depending on the rating, an air filter can remove pollen, bacteria, fungal spores, smoke, dust mites, and droplets. You likely use a pleated MERV-rated filter in your home or workplace, whereas higher efficiency filters like HEPA or ULPA are primarily reserved for health-care environments.
Filtered Particles
Bacteria
Fungal Spores
Respiratory Droplets
Dust Mites
Pollen, Dust, Debris
Implementation
High filter efficiency is correlated to reduced air flow ability, so it’s essential to find a filter suitable for the size and capacity of your specific ventilation system. MERV-rated filters are appropriate (and recommended) for most commercial and residential buildings. MPR and
FPR are the less common methods made to classify filter efficiency, however they function similarly to MERV ratings.
Compare MERV, MPR, FPR
To learn more about how to properly locate your filter slot and replace filters, click the button below for an instructional video.
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| MERV Rating |
Controlled Contaminants |
Min. Particle Size (μm) |
Application |
| 1-4 |
Pollen, Dust Mites, Sanding Dust, Textile Fibers, Spray Paint Aerosols |
> 10.0 |
Pre-filters, Residential AC Window Units |
| 5-8 |
Mold Spores, Dust Mite Debris, Pet Dander, Cement Dust, Hair Spray, Fabric Protector |
10.0–3.0 |
Better Residential, General Commercial, Final Filters, Industrial or Paint |
| 9-12 |
Legionella, Lead Dust, Auto Emission Particulate, Nebulizer Droplets, Humidifier Dust |
3.0–1.0 |
Superior Residential, Better Commercial, Hospital Labs, |
| 13-16 |
Bacteria, Respiratory Droplets, Cooking Oil, Tobacco Smoke, Insecticide Dust, Face Powders, Paint Pigments, Toner |
1.0–0.3 |
Hospital, General Surgery, Superior Commercial, Smoke Lounges |
Sustainability Implications
Air filters should be replaced or cleaned every 6-12 months. In buildings where there are pets, excessive smoke, or occupants with considerable allergies, filters should be replaced every 2-3months or less. Budget air filters, usually made of fiberglass, can be used as well but are less effective and require replacement every 30 days.
Filters are a necessary, but inexpensive way to improve indoor air quality. The cost of an air filter is typically based on size, material and efficiency. Lower-rated filters range from $5 to $20, whereas a MERV rating higher than 13 or a reusable filter can be up to $100. For a majority of buildings and residential spaces, air filters are a small cost, but high impact investment.
Air filters are not particularly harmful for the environment. They are typically made out of cotton, paper, fiberglass, or polyester. For a more environmentally friendly approach, purchase a reusable filter and avoid fiberglass or plastic-based materials.