Your HVAC technician has likely lectured you on the importance of changing your air filter every 3 months or 90 days. But what happens if you let that time go by? Before we dive into when you should change your air filter, let's start with the why. A general rule for pleated air filters (such as those made by FilterBuy) is to replace the filter every 90 days. As the filter accumulates more dirt, dust, and allergens from the air, its efficiency decreases.
The only way to be sure how often the air filter should be changed is to have a visual inspection of the filter every month. After a few months, you'll get an idea of how quickly it gets dirty. You should replace the filter every three to 12 months of use, depending on the size of the filter. For 1-inch-thick filters, the usual recommendation is three months. For filters that are 4 inches or thicker, 12 months will normally pass.
Pleated filters are often better than non-pleated filters, as they allow a larger surface area to capture dust, pet hair, and other debris that floats in the air. Some filter brands and retailers use alternative scales, such as the Home Depot Air Filter Performance Rating (FPR) system or the MPR (on 3M Filtrete air filters).You may need to replace the filter more often if you have some very furry pets, for example, or if you live in an area with a lot of air pollution, for example, due to wildfires. Air filters usually have a MERV (minimum efficiency reporting value) that determines the type and size of contaminants against which the filter acts. Any use will cause a certain amount of dirt to be trapped in the air filter; after all, that is its function.
However, some air conditioning systems have filters inside the return air ducts spread over several rooms in the house. During these months, contaminants in your home may increase, but the air filter doesn't trap them. Any pleated air conditioning filter can improve your home's indoor air quality by trapping dust, pollen and other small particles, as with a quieter, more passive vacuum. Children are more sensitive than adults to indoor air pollutants such as mold, dust mites, dander and pollen; so make your home an oasis by using quality air filters and replacing them before they become too clogged and dirty. Be sure to install the new filter facing in the right direction; look for arrows on the filter frame that indicate the direction of airflow. Using an air filter with a MERV rating higher than that recommended by the boiler or air conditioner manufacturer may affect its performance.
Air filters are usually made of spun fiberglass (the same thing that forms attic insulation) or pleated paper (26%) framed with cardboard for greater stability and stiffness. The secret is that they can capture tons of waste using a relatively porous filter material thanks to their enormous surface area through which dirty air has to pass - four times more filter material than a 1-inch filter. As air passes through a building's air conditioning system, air filters trap and collect large and small particles such as dust, allergens and microorganisms.
