A 2-fold air filter should be changed every 3 months, while a 3-fold air filter should be changed every 120 days. A 4-fold air filter should be replaced every 6 months, and a 5- or 6-fold air filter should be changed every 9-12 months. The only way to be sure how often your air filter needs to be changed is to visually inspect it every month. After a few months, you'll get an idea of how quickly it gets dirty and if you need to re-evaluate the frequency of replacement due to new pets or poor outdoor air quality.
Pleated air filters may need to be changed after sixty days, while fiberglass filters can only last up to thirty days. On average, air filters need to be changed every 90 days. An HVAC filter will usually last one to three months. If you wait too long to change the filter, indoor air quality will suffer.
As a general rule, lower home occupancy extends the life of the air filter, while higher home occupancy reduces it. For air conditioners, replace the filter every 30 days with cheaper fiberglass filters to avoid higher energy bills. Pleated and fiberglass filters can usually be accessed for routine cleaning and replacement. While these factors affect how often your air filter is changed, you should visually inspect it every month to check for excess particulate matter buildup. The MERV (Minimum Efficiency Reporting Value) scale provides professionals with a uniform standard for evaluating the quality of their air filters. Indoor air treatment systems, vents, and ducts are ideal places for bacteria, mold, and fungi to thrive.
When the air filter is clogged, the air conditioning unit requires a lot of extra work to circulate fresh air throughout the house; the additional work requires more electricity. Fiberglass filters, which are less expensive, are especially problematic since they require cleaning and changing them more frequently. Most air filter manufacturers recommend changing them every month or as soon as they succumb to exposure, also known as when mold grows or becomes saturated with airborne particles. To ensure your home's indoor air quality remains healthy and your energy bills remain low, it's important to inspect your AC filter regularly and replace it when necessary. The frequency of replacement depends on the type of filter you have installed in your system; however, it's best practice to visually inspect your filter each month.
