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How Often Should Home Air Filters Be Replaced?

Air filters need to be replaced more often than you might think. Dirty air filters can cause a world of trouble. Here's how often you should change your home air filter.

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change home air filter

You might believe that air filters serve one basic purpose: to clean the air that circulates throughout your home. However, that’s not technically true. The original purpose of home air filters was to prevent the HVAC system from damage. Improved indoor air quality is simply a byproduct! Air filters help clean the air indoors by trapping harmful pollutants such as dust, pollen and dander. For healthy air quality, it’s important to know when to change home air filters.

How Often Should You Change Home Air Filters?

The frequency with which you should change your home air filter depends on the type of filter, its thickness, the MERV rating and some special conditions. Let’s break down each factor.


The standard basic air filter is a 1-inch thick disposable filter. This type of filter needs to be replaced every 30-90 days. Other home air filters range from roughly 2-5 inches in thickness. It is generally recommended to replace such filters every four to six months as a baseline. However, thickness alone is not enough to determine how often to change the filter!

Filter Type

  • Pleated: A pleated air filter helps reduce the circulation of dust and other air pollutants due to greater surface area thanks to its accordion design. Pleated filters can be made of various fabrics or materials. Their efficacy depends on the material type.
  • Fiberglass: A fiberglass filter is fairly common and disposable. They are loosely wound and are not the best IAQ-focused filter choice.
  • Washable: Washable filters are reusable, making them an environmentally friendly choice. However, they must be well-maintained in order to prevent mildew and mold growth, thus they require frequent maintenance.
  • HEPA: High Efficiency Particulate Air (HEPA) filters are extremely effective with regard to filtration, but they significantly reduce airflow for the average home HVAC system.
  • Activated Carbon: An activated carbon filter effectively reduces VOCs and odors, but struggles to remove particulates such as dust, pollen and mold.
  • Media: Media filters, and even better, high-efficiency media filters offer superb air filtration without reducing airflow. It is the happy medium of air filters.

Special Factors

Special conditions to consider include whether there are allergy and asthma sufferers in the home or pets. The following chart provides a breakdown of how often to routinely check (at a minimum) your home air filter for buildup, based on various factors. And again, considering the wide range of air filters and different efficacy levels, view the ranges as an average!

FactorReplacement Range
Someone in the home suffers from allergies or asthma30 to 45 days
Ordinary Home, No Pets~ 90 days
Ordinary Home, One Pet~ 60 days
Ordinary Home, Multiple Pets20 to 40 days
Single-Occupant Home, No Pets~ 180 days

All estimates are tricky to do as a generalization. They are based on the average family home with an average occupancy level. Filter rating is also a very important factor.

MERV Rating

Overall, filters with lower MERV ratings should be checked and replaced more often than higher-rated filters. An air filter with a MERV 1-4 rating is significantly less efficient at filtering out pollutants. Check this MERV range often and change the filter whenever pollutant buildup is clear.

The middle-efficiency range of MERV 5-10 likely requires filter changes somewhere around two or three months. However, this mid-range really varies depending on other factors and filter material.

Air filters with a MERV 11 rating or higher rating can usually go between three and six months before replacing. Specifically, for high MERV ratings and greater thickness, these filters easily require only two filter changes per year.

How often should home air filters be replaced? Considering all the factors IAQ comic
Finding the best schedule to replace your home air filter means considering all the factors!

If you’re still unsure, more than likely, the home air filter you choose will have specific recommendations on the packaging.

The bottom line: prioritizing your and your family’s health and healthy indoor air means a clean air filter should be the priority. With this in mind, to ensure the cleanest air filter, you must take into account all of the factors listed above to determine the best filter timeline for your space.

What Happens if You Don’t Change Your Air Filter?

Neglecting home air filter maintenance can result in a plethora of home and health issues.

Reduced Airflow: A dirty air filter is clogged with dust and debris, which also reduces airflow. Ultimately, your HVAC unit will have to work harder to compensate, potentially leading to system failure or costly repairs.

System Failure: An HVAC unit that is working hard to circumvent clogged air filters is subject to overheating and other issues. Once a unit overheats, it is likely to break resulting in expensive repairs.

Increased Allergens: Those who suffer from allergies may notice increased fatigue, headaches and cold-like symptoms. This is due to the fact that major allergens aren’t being filtered out as effectively. Without a clean air filter, when the air is blowing, these particles circulate throughout your home.

Electricity Bill Increase: Reduced airflow from a dirty filter greatly stresses your AC unit and HVAC system. All of which increases your electricity or gas bill.

Overheating AC Unit: If you notice an increase in the actual temperature of your outdoor condenser unit, it may be indicative of a dirty air filter. This is determined by touching the back of the outdoor unit.

Dust: If you notice more dust settling on surfaces near the vents in your home, it could be another sign that the air filter is dirty. Check surfaces further away from the vents, if they are not as dusty, then the air filter is the problem. Also, as a test, hang a white sheet within several inches of the vent and see if the sheet turns gray, which again shows it’s time to change the home air filter.

Which Air Filter Is Best for You?

Changing home air filters is quick and easy! If you’re looking for the perfect home air filter, one that provides your space with cleaner, filtered air and healthy indoor airflow, look no further than a MERV 13 pleated media filter. We suggest this option because it truly combines the best features of every category.

You’ll likely only have to replace a MERV 13 filter every six months! (Depending on those special conditions, of course.) By nature these filters are low maintenance, saving you both time and money. They’re also high-efficiency, meaning improved overall air quality and a healthier indoor space!

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