If you’re looking for improved protection for your HVAC system from dirt buildup and indoor air that’s free of contaminants, looking at the air filter in your furnace (or heat pump or air conditioner) is a step in the right direction. In many cases, the air filter installed in your furnace is likely the style that came pre-installed by the manufacturer, who generally utilizes the lowest-quality filter to trap only the largest particles for basic HVAC system protection.
How to Choose a Better Air Filter
It’s possible to upgrade the air filter for improved results, but the technology can be confusing, and installing a filter that restricts airflow can damage the system. Here’s what you need to know about air filter technology options:
- Minimum efficiency reporting value (MERV) is the ratings system that reveals air filter capabilities
- The MERV scale runs from 1 to 20; however, filters for residential applications run from MERV 1 to 16. Only high-efficiency particulate air (HEPA) filters are rated MERV 17 to 20.
- Manufacturer-installed filters typically range from MERV 1 to 4, trapping particles larger than 10 microns.
- Filters rated MERV 5 to 13 employ tightly woven filter surfaces that trap smaller particles, or those larger than 1.0 microns.
- The MERV 14 to 16 filters trap particles 0.3 microns in size, but generally restrict airflow too significantly for residential use.
- The U.S. Environmental Protection Agency (EPA) recommends MERV 7 to 13 filters, believed to be almost as efficient as HEPA filters, as it’s believed the filter’s media becomes more dense – and more efficient – as it fills up with particles; however, in order for these filters to perform, they must be changed regularly.
- HEPA systems perform most efficiently, capturing nearly 100 percent of microns 0.3 in size, compared to mid-range filters that capture between 50 to 80 percent of particles 1.0 microns or larger. HEPA systems are more expensive to purchase, as it’s a separate filtration system, not a filter installed in the furnace. Using a dedicated blower, the system removes a portion of air moving through the HVAC system, filters it, and then restores the air.
For more information about air filter technology, please contact us at Ernst Heating & Cooling. We’ve served homeowners throughout the Metro-East since 1951.
Our goal is to help educate our customers in Hamel, Illinois and surrounding areas about energy and home comfort issues (specific to HVAC systems). For more information about air filter technology and other HVAC topics, download our free Home Comfort Resource guide.