For optimal air quality and energy efficiency, it is important to replace your MERV 13 filter regularly. The MERV rating system, which stands for Minimum Efficiency Reporting Value, measures the efficiency with which air filters remove particles from the air. Generally, filters with a MERV rating of 8, 11 or 13 should be changed at least every three months. However, for the best filtration and healthiest air in your home, it is recommended to change the filter every two months.
If you have pets, children or people with allergies in your space, it is advised to replace the filter more frequently. Additionally, if you notice that the filter is covered in dust, it should be replaced immediately. For MERV 3 air filters of 1, 2 and 4, they are designed to last approximately three months. Meanwhile, MERV 13 replacement filters for the whole house must be replaced every six months.
It is important to replace filters regularly because the older an air filter is, the less bacteria and dirt it removes from the air. This will worsen indoor air quality and increase energy costs. To obtain high MERV ratings and greater thickness, these filters easily require only two filter changes per year. If your oven can handle it, use a filter with a MERV rating of 12 such as the Nordic Pure Filter (available on Amazon).
However, how often you should change your home air filter depends on the type of filter, its thickness, the MERV rating and some special conditions.