How Often Should You Change Your A/C Filter?
October 20, 2025 By: One Way Heating & Cooling
When was the last time you changed your air conditioner filter? If you can’t remember, you’re not alone. Many homeowners overlook this small task, even though it has a major impact on how well your A/C system runs. A dirty filter can cause higher energy bills, poor airflow, and unnecessary wear and tear on your HVAC unit. Worse yet, it can affect the air you breathe every day.
At One Way Heating and Cooling, we work with homeowners across the region who want to keep their HVAC systems running efficiently and reliably. One of the most common questions we hear is, “How often should I change my A/C filter?” The answer varies based on several factors, but once you understand what those are, it’s easy to build the right air condition maintenance schedule.
Let’s take a deeper look at why air filter changes matter, how frequently you should do it, and what happens if you skip it too long.
Why Changing Your Air Filter Matters
Air filters are the unsung heroes of your HVAC system. While small and relatively inexpensive, they serve a big purpose: keeping dust, pollen, pet dander, and other airborne contaminants from circulating through your home. They also protect your system’s components from buildup that can lead to mechanical issues.
When the filter becomes clogged, airflow is restricted. This means your system has to work harder to move air, increasing energy consumption and straining essential parts like the blower motor and evaporator coil. Over time, this can lead to costly breakdowns or even system failure.
Not only does a clean air filter improve system performance, it also helps maintain indoor air quality. For families with children, pets, or anyone who suffers from allergies or asthma, regularly changing the filter can help reduce symptoms and create a more comfortable home environment.
General Guidelines for Filter Changes
So how often should you actually replace your air filter? While the typical answer is every one to three months, the real frequency depends on your household, filter type, and local environment.
Type of Filter
Filters come in various materials and thicknesses. Lower-cost fiberglass filters usually need to be changed every 30 days because they trap fewer particles and become dirty faster. Pleated filters, which are more efficient and have a larger surface area, can often last 60 to 90 days. High-efficiency filters, including HEPA options, may last up to three months or more, though these are usually found in systems that are equipped to handle their higher resistance to airflow.
Size of Household
The more people in your home, the faster the air filter will fill up with dust, skin cells, and other debris. A single-person household with no pets may only need to replace the filter every two to three months. A family of five with a busy household should plan on checking their filter monthly.
Pets in the Home
If you have one or more pets, you’ll likely need to change your filter more often. Pet hair and dander quickly clog filters, especially in high-shedding breeds. In households with multiple pets, monthly filter changes are often necessary to maintain proper airflow and air quality.
Allergies or Respiratory Conditions
If anyone in your household has allergies, asthma, or other respiratory conditions, you should consider changing your filter every 30 to 45 days. Cleaner filters help reduce the amount of airborne allergens and can make a noticeable difference in breathing comfort.
Climate and Environment
Where you live also plays a role in how quickly your filter gets dirty. If you’re in a dry, dusty area or near construction or agricultural fields, particles in the air can clog the filter faster. Even seasonal factors like spring pollen or summer wildfire smoke can impact filter performance. If you live in an area with high particulate levels, it’s smart to check your filter every 30 days.
Frequency of A/C Use
During peak usage seasons—hot summers and cold winters—your HVAC system runs more often and pushes more air through the filter. This means filters need to be replaced more frequently than during milder seasons when your system isn’t working as hard. Even if you don’t use your A/C daily, if you leave the fan running continuously, your filter will still be collecting particles.
Warning Signs Your Air Filter Needs to Be Replaced
Even if you’re not sure how long it’s been since your last filter change, your home will likely show signs that it’s time.
If you notice more dust on surfaces than usual, this could be a result of your filter not trapping airborne particles effectively. Reduced airflow from your vents is another common indicator. If your air conditioner seems to be running longer to cool your space or if energy bills are climbing without a clear reason, your filter may be clogged.
Other red flags include musty odors, a noticeable drop in indoor air quality, and increased allergy or asthma symptoms. These issues often resolve quickly once a clean filter is installed.
What Happens When You Don’t Change It
Putting off filter changes may not seem like a big deal, but over time, it can lead to major problems with your HVAC system.
When airflow is blocked, the entire system becomes less efficient. Your air conditioner has to work harder to push air through, which increases energy consumption and wears out components faster. The evaporator coil can freeze due to restricted airflow, and dust buildup can lead to overheating or motor failure.
Neglecting filter changes can also void your manufacturer’s warranty in some cases, since regular maintenance is often a requirement. Plus, replacing major components—or the entire system—is far more expensive than keeping up with basic filter maintenance.
How to Change Your A/C Filter Correctly
Changing your air filter is one of the easiest DIY tasks for homeowners, and it doesn’t take long.
Start by turning off your HVAC system for safety. Locate the filter—usually near the return air duct, in a wall or ceiling vent, or inside the air handler unit. Slide out the old filter and check the size printed on the frame. Make sure to buy the correct replacement, and check that the airflow arrows on the new filter point in the right direction when installing.
Once the new filter is in place, turn your system back on. It’s helpful to mark the installation date somewhere on the filter or set a reminder to check it again in 30 days. Even if you don’t change it monthly, regular inspections will help you stay ahead of problems.
Should You Use a Higher MERV-Rated Filter?
MERV, or Minimum Efficiency Reporting Value, measures how well a filter traps particles. The higher the MERV rating, the finer the filtration. Residential systems typically use filters with a MERV rating between 8 and 13. While higher MERV filters capture smaller particles, they also restrict airflow more than lower-rated filters.
Before switching to a high-MERV filter, it’s a good idea to check if your system can handle it. Using a filter that’s too restrictive for your system can lead to poor airflow and reduced efficiency. If you want better air filtration and aren’t sure what your system supports, talk with a licensed HVAC technician.
Partner with One Way Heating and Cooling for Hassle-Free Maintenance
Staying on top of air filter changes is one of the most cost-effective ways to keep your HVAC system running at peak performance. But we understand that life gets busy and home maintenance tasks can fall through the cracks. That’s where One Way Heating and Cooling comes in.
Our professional HVAC maintenance services include regular inspections, filter replacements, system tune-ups, and expert advice tailored to your home. Whether you need seasonal maintenance or help choosing the right filter for your home’s air quality needs, our experienced technicians are ready to help.
Let us take the guesswork out of your HVAC maintenance and keep your home comfortable year-round.
Contact One Way Heating and Cooling today to schedule your next A/C maintenance visit and stay ahead of costly breakdowns with reliable air filter replacement service.