Fortunately, most 20x25x4 air filters last between six and eight months. This means that the average homeowner won't need more than two 20x25x4 air filters in a year. On the other hand, a one-inch air filter should be changed every two or three months. Fiberglass air filters are the most affordable option, but they are not as effective at trapping dust and particles in the air.
They usually need to be changed every 30 days or less. Most air filter manufacturers and HVAC companies recommend changing the air filter every 90 days or 3 months. This may vary depending on the location of your home (for example, dry and dusty climates), if you have pets, and the age of your system and equipment. If you have pets in the household, you should consider changing the filter every 60 days or 2 months.
For households with multiple pets or people with allergies or respiratory conditions, we recommend changing the filter every 20-45 days. Vacation homes or empty homes that don't see much use can wait to change filters every 9 to 12 months. The more you use your home, the more often you should change the air filter. A general rule of thumb for pleated air filters (such as those manufactured by FilterBuy) is to replace the filter every 90 days. As the filter traps more dirt, dust and allergens from the air, its efficiency decreases.
If you need to replace the filter more often, consider factors such as pet dander, allergies, and respiratory conditions. Excess dust, pet dander, and other allergens floating in the indoor air can worsen symptoms such as coughing, sneezing, and runny nose. During periods of the year when HVAC equipment operates frequently, air circulates more times around the home compared to times when the HVAC system is used sparingly. By installing a new air filter, your air conditioning unit will operate more efficiently and reduce your energy bills. There are high-efficiency filters that are designed to filter small particles of bacteria, mold and mildew, but standard MERV 8-11 filters will only block the largest particles of dust, dirt & hair. Children are more sensitive than adults to indoor air pollutants, such as mold, dust mites, dander and pollen.
To ensure clean air for your family's health and comfort, use quality air filters and replace them before they become too clogged and dirty. If there are allergy sufferers or asthmatics in your home, it is especially important to change your air filter regularly. People with allergies, asthma or other respiratory conditions are sensitive to most airborne particles. If the air filter usually lasts 90 days, you should change it every 30 days during peak summer and winter months when your system is working most intensively. Allergy sufferers will benefit from more frequent air filter changes. If replacing the air filter is simply out of the question for an extended period of time, going beyond 90 days will not cause irreparable damage to your air conditioning system.
However, you will no longer be able to filter the air properly, allowing dust and contaminants to enter your HVAC system.
