Air filters are not all equal. Generally speaking, most low-end fiberglass filters barely do an adequate job of keeping the largest airborne particulates out of your HVAC system. The particles that do get through not only end up as dirt inside your system, causing it to work inefficiently, but also recirculating in the supply air and lowering indoor air quality. Here’s why a better quality air filter might be good for your home.
Better quality air filters for residential HVAC systems are usually pleated and made of dense material to do a better job of capturing particles. Filters rated by the minimum efficiency reporting value (MERV) system usually fall within the following categories:
- MERV 1-4: Filters capture only the largest particles.
- MERV 5-7: Filters do a somewhat better job of trapping smaller particles, and may be adequate for most households.
- MERV 8-12: Filters do an excellent job of capturing most particles found in a typical household, and also do not significantly slow down airflow.
- MERV 13 and above: These filters are usually found in residences where an occupant has a health issue requiring filtration of even the smallest particles. Higher efficiency filters may be found in research, hospital or manufacturing settings. HVAC systems that use this level of filtration must be modified to allow for reduced airflow.
The key in selecting the right filter for your home is to balance keeping the smaller particles out of your system’s machinery and out of your home’s air, while maintaining correct air flow. A filter that is too dense will cause a condition called pressure drop, and your equipment will work inefficiently. Pressure drop can also lead to system breakdown.
Besides the mechanical filtration types described above, you might also consider electrostatic filters, which catch particles with an electrical charge. These filters are washable and reusable, so they generally cost more than mid-level efficiency mechanical filters.
For more on the importance of air filter quality, contact Roth Heating and Cooling. Our customers recognize us as the top heating, cooling, plumbing, electrical, drain and appliance service in Portland.