How Often Should You Change Your Air Filter? Know the Facts!

Air Filter

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Has your air conditioning suddenly stopped working? You have probably been advised that you need to change your air filter. But how often should you change your air filter?

How Often Should You Change Your Air Filter?

So how often should you change your air filter? Unfortunately, the answer is not very cut and dry. However, a good rule of thumb is that you should change your air filter every 30 days. At the very least, you should check your air filter every 30 days.

The long answer is there are several factors that affect how often should you change your air filter. These include the number and types of pets you have in your home, the type of flooring you have, where in the country you live, and more.

Factors That Affect Air Filter Performance

The first factor that affects the performance of your air filter, and how often should you change your air filter, is the quality of the air filter you purchase. Poorer quality air filters will need to be replaced less frequently because they usually let more dust pass through. Pleated filters, on the other hand, catch more dirt, dust and other allergens, so they need to be replaced more often. Finally, media filters catch a great deal of dirt and dust. However, because their surface area is so much greater, they usually last longer.



Importance Of Changing Your Air Filter

While there is no set schedule for how often should you change your air filter, it is important to change it regularly. Air filters filter your air, and this can protect you from harmful allergens, such as pet dander, dust and pollen you may have tracked inside.

HVAC Performance

It is important to make sure your air filter remains clean because a dirty air filter reduces airflow in your home. This, in turn, puts enormous strain on your HVAC system and reduces its efficiency. Clean your air filters, if you can, to save money. But do not fail to replace them when the time comes. To make this easier on you, purchase five or six air filters at a time. This guarantees that you will have them on hand when yours, inevitably, need to be replaced.

Heating And Cooling Consistency

If you do not replace dirty air filters, air struggles to circulate in your home. This means your bedroom or living room may not get as warm or cool as you need them to be for your comfort. Since the temperature sensors that regulate your HVAC system detect that a given room is not the appropriate temperature, it will continue to run. This strains the fan motor and increases your power bill.

HVAC Damage

Clogged air filters mean cooled or heated air struggles to leave your air conditioner, furnace or heat pump. This puts your HVAC system at significant risk of freezing up or overheating. As a result, you will be paying for electricity, natural gas or oil but will not feel a change in the indoor temperature.


Air filters remove allergens from the air, such as pet dander, dust, dust mites, tobacco smoke, mold spores and pollen. Even if you only suffer from light to moderate allergies, you do not want these allergens floating around in the air you breathe. Air pollution in your home can also trigger asthma attacks.

While clean air filters remove mold spores and other air pollutants, a dirty air filter can lead to the accumulation of moisture. This is the perfect breeding ground for colonies of bacteria or significant mold growth. These only strengthen the barrier to air circulation. Moreover, if the colonies or growth spread to the wrong side of your air filter, more allergens and pollutants can be introduced into the air inside your home. Finally, if mold or bacteria spread all the way to your HVAC system, the entire system could easily become damaged.

More Cleaning Required

An air filter operating at maximum efficiency keeps your indoor air clean. Contrastingly, if air does not circulate efficiently because your air filter is dirty, pollutants can settle inside your ducts and on household surfaces. This means you will need to clean your home more often.

Where To Find Your Filter

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If you have just moved into a new home, you may be wondering where your air filter is. Air filters are almost always located right next to the air handler for your air conditioning system or furnace. You can identify the air handler as the large box housing the fan and fan motor. It will be inside a one-inch wide removable or hinged cover or in your attic.

If you have several returns in your home, look for an air filter inside each return. If you have more than one HVAC system installed in your home, look for an air filter at the air handler and inside the returns.

How To Save Money

You can save money by purchasing cheap air filters which are ineffective at cleaning your air. However this is the wrong way to go about saving money. Rather, buy pleated filters and check them 30 days later. If they still look clean, check again in 15 days. Continue checking your pleated air filters every 15 days until they appear dirty.

Once your pleated air filters look dirty, vacuum them. This works if the air filters are dirty from dust bunnies and hair. If, however, your air filter is dirty because of something like grease, this cannot be vacuumed out and you will have to replace your air filter. Another helpful tip for saving money on your air filters is to buy them in bulk online.

What About The Return Air Filter?

You do not need to hire a professional to replace your air filter. Depending on the type of HVAC system you have installed, there may be an extra air filter in the return ducts. To discover if you have a return air filter, go to your return air vents. If your cover has screws, unscrew them. If your cover has tabs, pull the tabs. Take the cover off the wall. Look inside for an air filter.

If there is a filter inside your return duct, pull it out and take note of the size. Make sure the type of filter in your return duct is recommended by the manufacturer. If you find your return air filter to be dirty, replace it with one the appropriate size and type.

Why Is The Type Of Filter Important?

The type of air filter in your return duct is important because it affects the airflow in your home. HEPA filters are extremely pricy and catch smaller debris. However, this will restrict the airflow in your home. This reduced airflow leads to greater pressure on your HVAC system. This, in turn, causes inefficiencies in heating and cooling. This means your heating and cooling bill will be significantly higher than is optimal and your HVAC system will need far more frequent maintenance, part replacements and repairs.

The Bottom Line

There is no hard and fast rule for how often should you change your air filter. If the residence is a single-occupant or rarely used home, and you do not have pets or allergies, you can probably get away with changing your air filter every six months to a year. If you live in a typical suburban home with a partner, two kids and no pets, you should probably change your air filter every 90 days.

If you have a dog or cat, you will probably need to change your air filter every two months. Finally, if you have several pets or allergies, you should, in fact, change your air filter every 30 to 45 days.

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