Filtering out particulates has become quite the hot topic lately, especially when talking about air quality in indoor spaces. To be honest, the air quality inside your home should always be a priority – after all it has a tremendous effect on your health during flu and allergy seasons.
Air quality becomes especially important if you have a forced air system in your home – typically called a furnace, that has ducts and vents (no radiators, baseboard heaters, or radiant heat). Changing your filters regularly is important because they do a better job than dirty ones at blocking microorganisms, dander, and other allergens that are in your home. Plus a clean air filter can also help lower your energy bills because your system doesn’t have to work as hard, which in turn can lengthen the lifespan of your equipment.
Now that we’ve covered what filters do and why they are important, let’s talk about the different types:
- Flat panel: The most budget-friendly air filter. Traditional disposable flat-panel models have fibers stretched over a framework. They are easy to install, inexpensive, and the most porous.
- Pleated: These moderately priced, disposable filters are pleated and use dense screens of cotton or plastic fibers to remove particles from the air. The pleats provide more surface area for filtration and allow the filter to catch more debris than flat-panel filters.
- Electrostatic: These can be flat or pleated, washable, or disposable and are electrostatically charged to trap more (and smaller) particles such as pollen, smoke, or bacteria.
- Washable/re-useable: Available in both flat-panel and pleated options, and they can be hosed down with water or vacuumed to remove particle buildup. Washable filters usually have a life span of two to four years, depending on use.
- HEPA filters: The term high-efficiency particulate air or HEPA is assigned to any filter that consistently removes at least 99.97 percent of particles in the air that are 0.3 microns or larger. These are commonly used in hospitals, laboratories, and other settings that require extremely clean air, but many homeowners who suffer from allergies or have a compromised immune system choose to use these filters as well. These are the most expensive and keep in mind that not all HVAC systems are designed to handle the super-dense HEPA filters.
What are MERV, MPR, and FPR?
These acronyms are used to describe the tightness of the filter weave with a higher number indicating a finer filtration. The only difference is who manufactures them.
- MERV, or Minimum efficiency reporting value, is a measure developed by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE); MERV ratings range from 1-20.
- MPR, or Micro-Particle Performance Rating, pertains only to products developed by the 3M company; typical MPR ratings range from 300 to 2200.
- FPR, or Filter Performance Rating, is a filter rating system developed by Home Depot for the brands sold through its stores, including Honeywell; it uses a 1-10 rating scale.
How do you compare MERV, MPR, and FPR values?
There is a conversion table below that shows comparable values:
| MERV | MPR | FPR |
| 6 | 300 | n/a |
| 8 | 600 | 5 |
| 11 | 1000-1200 | 7 |
| 13 | 1500-1900 | 10 |
If you have questions about the best HVAC filter to use for your furnace, give us a call. We’re happy to point you in the right direction.
