If you’ve never upgraded the air filter in your HVAC equipment, you’re probably still using a very basic, low-grade filter. There are other filter options available, and you can choose a more effective one by using MERV ratings.
MERV, or Minimum Efficiency Reporting Value, is a ratings system that designates an efficiency to air filters based on their ability to filter out pollutants of differing sizes. It’s important to keep in mind, however, that as a filter becomes more efficient, it also resists airflow—and that’s air your furnace and A/C desperately need in order for the equipment to function efficiently, and to avoid wear and tear on its internal components.
MERV ratings can be broken down into three basic categories:
- Flat filters, rated MERV 1-4, are the most commonly used filter that manufacturers or contractors will pre-install in a system. They are designed to trap larger particles in order to keep the HVAC equipment clean, but they aren’t designed to impact your indoor air quality. So they don’t trap smaller particles, like dust mites, bacteria, pet dander and mold.
- Medium-range filters, MERV 5-13, use a pleated or extended filter surface to perform at a higher level of efficiency. With more overall surface space, and often using dense materials, these types of air filters are ideal for residential use. They trap more particles, both small and large, and ensure necessary airflow.
- Higher-efficiency filters, with MERV ratings between 14-16, are generally not used for residential applications, as their materials are too dense to allow sufficient airflow.
Homeowners are generally advised to use a filter with a MERV rating around 8.Some experts report that these mid-range filters can perform higher than rated. Once the filter gathers some particles in its materials, it’s believed that the filter becomes more efficient, with the particles creating more density within the surface material.
Using MERV ratings, you can select an air filter that helps your system perform, while improving indoor air quality. For expert advice when selecting a filter, contact Arpi’s Industries — serving Greater Calgary-area homeowners for almost 50 years.
Our goal is to help educate our customers about energy and home comfort issues (specific to HVAC systems). For more information about MERV ratings and other HVAC topics, download our free Home Comfort Resource guide.