In general, most air filter manufacturers and HVAC companies suggest changing the air filter every 90 days or 3 months. Fiberglass air filters are the more affordable option, but they are less efficient at capturing dust and particles from the air. These filters should be changed every 30 days or less. Air filters and oven filters should be inspected at least once a month to determine if they need to be replaced with a clean, new filter.
When you remove the air filter from the air conditioner, if you bring it closer to a light source, you can see if the filter is dirty or clogged. If you can't see the light through the filter, it's time to change it. Accordion filters are usually of higher quality, as their shape and design allow more air to pass through the filter. If you live in a temperate climate that only needs air conditioning for a few weeks during the summer, you may be able to go months without changing your filter.
However, the more often you use an air conditioning system, the faster the air filter will fill with dust and dirt. For milder to moderate allergies, residents will want to try replacing air filters every 30 days. The fewer occupants there are in a house, the less pollutants and debris will accumulate in the air filters. As outdoor dust or pollution increases, so does the need for replacing indoor air filters on a more regular basis.
As a general rule, you'll want to replace your home's pleated air filters and boiler filters every 90 days. It's good to know how often professionals recommend changing the air filter, but there are also some signs that may indicate that it's time to do so. The longer the filter stays in place, the more dirt, dust, and allergens will be trapped, clogging the filter and decreasing its efficiency. If you have a pet, you'll want to change the air filter every 2 months, especially when winter turns to spring and summer to fall.
Homeowners may forget to change their air conditioning filters for months at a time, which can cause dust, debris, and allergens to build up. The manufacturer of an air filter usually explains how often it should be replaced in its installation instructions. During these months, pollutants in your home may increase, but the air filter doesn't catch them. Air filters trap pet hair, dust, and other irritating particles so that your air conditioning system returns fresh, clean air to your home.