In general, most air filters should be changed every 90 days or 3 months. This may vary depending on the location of your home, if you have pets, and the age of your system and equipment. Pleated air filters are more expensive at first, but they are also more efficient at trapping particles and can last up to 90 days, depending on use. A general rule for pleated air filters (such as those manufactured by FilterBuy) is to change them every 90 days.
As the filter traps more dirt, dust and allergens from the air, its efficiency decreases. It's important to consider the factors mentioned above to determine a replacement program and decide what type and quality of filter you should use. In any case, it's a smart and proactive policy to inspect at least the air filter every 6,000 miles (9,656 kilometers). If someone in your family has mild to moderate allergies, you can put a better air filter on it or change it even more often.
If you want a pet that is hypoallergenic or doesn't lose hair or hair, you may not need to replace your air filter as much. For every dog that has a shed of hair, expect to replace the filter a month earlier than you would with a pet-free home. While a filter with a higher MERV rating should last longer, it can also restrict airflow in your home. If there is a visible layer of dirt that covers most of the surface of the filter and is thick enough to hide the filter material itself, it is a sign that the filter has been in the air conditioning system for too long.
If you have young children in the house, it's a good idea to use high-quality pleated air filters and replace them every two months. If you've changed your air filters and you're still experiencing these problems, it's a good idea to call a professional to help you address the root problem. Numerous contaminants and debris, including excess dust, can cause air filters to become clogged and reduce air circulation throughout the home. If you've driven more than 6,000 miles since the last time you changed your air filter, it's probably time to change it.
This is especially true if homeowners begin to notice particles floating in the air that subsequently cause allergic reactions. And if you buy an older system, plan to replace the filter more frequently to maintain filter quality.