Finding a MERV filter that works for your family, and helps your furnace to function efficiently, is actually a rather simple process. All you need to know is how MERV, minimum efficiency reporting value, works, and which MERV filter will work with your system.A MERV rating, developed by the American Society of Heating, Refrigeration & Air-Conditioning Engineers (ASHRAE), is designed to show how well a filter traps particles, and the size of particle it can trap. Higher-rated MERV filters will trap smaller particles. Low-efficiency filters Rated MERV 1-4, these filters offer the most basic level of protection for your furnace and your home’s air. They aren’t able to trap smaller particles very well, but do a decent job of capturing larger particles. If you’ve never evaluated your furnace filter before, it’s likely that its MERV rating is within this range. Mid-efficiency filters These filters, rated MERV 5-13, generally have an expanded surface, either through a pleated design or some other technology that increases the filter space, so they can trap more particles. The density of the filter’s surface is also critical to efficiency, and mid-range filters have denser fibers. Overall, these filters are the best choice for residential use because they allow enough air to flow through the filter, while balancing the capacity to trap particles of both small and large sizes. High-efficiency filters -- including HEPA It's possible to purchase a higher-efficiency filter, rated MERV 14-16, or a High Efficiency Particulate Air (HEPA) filter, rated MERV 17-20; however, both types of filters greatly restrict airflow and are not recommended for use with residential systems. For the ultimate in indoor air quality, you can opt to purchase an air-cleaning device that can be used alongside your HVAC system, which will use a higher-efficiency filter without affecting airflow.If you suspect that your furnace’s MERV filter could use an upgrade, or for any other heating and cooling questions, contact Air Assurance Heating, Cooling & Air Quality today! We've been serving homeowners in the Greater Broken Arrow area for more than 30 years. Our goal is to help educate our customers about energy and home comfort issues (specific to HVAC systems). Air Assurance services Tulsa, Broken Arrow and the surrounding areas. Visit our website and get started today! Maintenance Checklist image via Shutterstock