How Often Should You Change Your AC Filter?

In 2019, the global HVAC systems market size was $240.8 billion, and it shows no signs of going down any time soon. The tremendous market growth comes as more home and business owners realize the importance of a functional AC to ensure a comfortable and healthy living space and promote energy efficiency.

There is no better way to enjoy the benefits of AC than by regular HVAC maintenance. Neglecting AC maintenance compromises the system’s performance, causes energy inefficiency and reduces the lifespan of the HVAC unit.

A big part of AC maintenance is changing its filter. Keep reading this guide for insights on how often to change your AC filter.

When to Change AC Filter

How Important Is the Air Conditioner’s Filter?

The air conditioner filter lives up to its name. It filters the air. Besides eliminating dust, pollen, and other allergens from the air, air filters protect the AC from large particles in the air and, in return, save the system from damage.

Although you can get away with operating your air conditioner without a filter, the privilege is short-lived. Running the system without a functional filter for more than 8 hours could result in severe damages, not forgetting it will lower air quality in your space.

Related Article Know More About AC Filters

Why Do You Need to Change Your AC’s Filter?

According to the US Department of Energy, regular AC maintenance improves the system’s performance and increases its energy efficiency. Therefore, replacing the air filter is a critical part of AC maintenance. Some benefits of changing your AC’s filter within the recommended period are:

Best Performance During Summer

Failure to replace your AC’s filter every three months results in dirt and debris accumulation in the filter, which increases the workload of the AC. This could result in unexpected wear and tear of the cooling system during summer, a time when you need it the most.

Reduced Chance of Breakdowns

As mentioned earlier, the air filter protects the AC from large particles in the air that could compromise its efficiency. As the filters age and deteriorate, they are bound to release debris and fibers. When the debris gets to the moving parts of the AC, it can result in a mechanical breakdown.

Avoid such mishaps by ensuring that your air filters are always in their best working condition to avoid the expensive costs of repairing or replacing the cooling system. Change the filters regularly before excess dirt accumulates on them.

Improved Indoor Air Quality

A functional air filter cleanses the air by filtering dust particles and pollutants. In return, you get high-quality and fresh air to breathe. This is critical, especially if you have pets or anyone in your home who is allergic to dust.

Nonetheless, you cannot enjoy the benefit of AC with a broken filter. Change it regularly to ensure its optimum performance.

Why Change AC Filter

How Often Should You Change Your AC’s Filter?

The general recommended period to change your AC is 90 days, but some may take longer than others. If you use the AC daily, the filter will wear faster than running the cooling system occasionally. Similarly, if you use a less costly fiberglass filter, you will need to change it every 30 days.

The longer you wait to change the AC’s filter, the higher the chances of dust and allergens getting trapped and clogging the filter. Consequently, this decreases the efficiency of the system and may result in a breakdown.

Other critical aspects to help you determine how often to replace your air conditioner filter are:

  • Do You Have Pets?
    If you are a pet owner, it’s best to change your filter every two months. The reason being, the filters are forced to work harder to eliminate the pet fur and odor, making them wear out faster.
  • Are Any of Your Family Members Asthmatic?
    Allergic and asthmatic individuals are more sensitive to air particles. Therefore, you must ensure that your filter can eliminate 99% of dust particles and allergens from the air by changing it every six weeks.
  • Do You Have Kids?
    Kids are also super sensitive to allergens and dust. If you have children, you want to keep the air quality at its highest levels. Try as much to change the air filters every two to three months.

Cleaning Vs Changing AC’s Filter

If you haven’t changed your AC filter for a long time, the chances are that you have lots of dirt and debris buildup in the ductwork. Cleaning the filters regularly is critical to prevent dirt buildup, but it gets to a point where changing it is the only solution to maximize its operation. Therefore, cleaning should not be an excuse for not changing your filters after 90 days.

Cleaning vs Changing AC Filter

Factors That Affect The Lifespan Of The Air Conditioner’s Filter

A lot comes into play when determining the lifespan of AC’s filters, including:

  • Frequency of Use
    The more frequently you use your AC, the higher the chances of filters wearing out sooner.
  • The Size of the House
    The size of your house dictates how hard the filters work to ensure high air quality. Thus, if you have a big house, the filters will wear out faster than a small one.
  • The Quality Of Air At Home
    The amount of dirt and pollutants in the air determines how much energy the filters need to clear the air. If the air is dirty, a lot of particles will accumulate on the filters within a short period, causing them to wear out.

How to Know That Your AC Filter Needs Changing

There are many reasons why you need to change your AC filter. Here are the most common:

The Air Conditioning Is Too Hot

The obvious sign that it’s time to replace your air filters is when the back of the air conditioner is too hot. When excess dirt accumulates on the filter, you may even notice hot air coming from the AC.

The cause of this issue is because a clogged filter will force the cooling unit to work harder to regulate temperatures, causing it to overheat.

The Air Isn’t Cold Enough

A clogged air filter hinders the cool air from passing through, making your space feel warmer than usual. Therefore, if you notice that your AC is not cooling air as efficiently as before, the first place to check should be the air filters.

The Electricity Bill Has Increased

A broken air filter forces the air conditioner to work harder and use more energy to regulate temperature and improve air quality. This issue causes the energy bills to be unexplainably higher.

You’re Suffering More Allergy Attacks

Asthmatic and allergic individuals should be more proactive in changing air filters. You cannot afford to live in a room with poor air quality. Otherwise, you risk experiencing more attacks. If you notice an increase in allergic symptoms, the chances are that the AC filters are not doing a thorough job of cleansing the air and need immediate replacement.

There’s More Dust Near the Air Vents

Another sign of a bad AC filter is dust on the furniture or surfaces near the vents. You can test this by placing a white sheet a few inches from the vents for a few hours. If the sheet changes its color, the filter is dirty or broken and needs changing.

Problems Caused By Not Changing Your AC Filter

Failure to replace your AC filter within the recommended period may result in costlier problems, including:

The AC Unit Will Break Down Quicker

Without a functional AC filter, the condensation drain cannot drain moisture from the system effectively. Consequently, the condensed air will accumulate on the Freon tubing before it starts dripping down the pan. The water will cause damage to the entire AC unit in the long run.

Decreased Cooling Comfort

If the air filters are dirty, clogged, or broken, they prevent adequate airflow through the AC system. Lack of air causes system inefficiency, meaning that it will take longer to cool the air in your home to your desired temperatures.

Poor Indoor Air Quality

A functional air filter is liable for keeping dirt and allergens from circulating through the AC. If the air filter fails, the dirt will pass through the AC and end up circulating through your space.

People Also Ask (FAQ)

Why is my AC filter not getting dirty?

AC filters are made to filter all the air that passes through the AC system. However, it must be well fitted to capture all the air that passes through the system. If your AC filters never get dirty, the chances are that it is not well fitted; thus, no air passes through it.

Can you run AC without a filter?

Yes, you can operate your AC without a filter, but doing it for more than 8 hours results in a system breakdown. Also, the quality of air in your space will be compromised.

Can I clean my air filter instead of replacing it?

Cleaning your air filter is essential, but that’s not reason enough to skip replacement. You can clean a dirty filter. Nonetheless, you cannot improve the performance of a broken filter by cleaning it.

Is it worth it to change the air filter every month?

The AC filter replacement time depends on the quality of the filters, frequency of use, and if you have pets or allergies. Although the recommended period for replacing the filters is three months, doing it after one month is the best choice if you have small kids, you are allergic, have pets, or your filters are not the best quality.


If you are unsure when to change the AC filter, check all the highlighted factors above to make a sound choice. HVAC filter replacement frequency may differ from one individual to the next, but there is only one goal, to ensure maximum efficiency of the AC.

Josh Mitchell

Josh Mitchell

My name is Josh and I am obsessed with DIY and improving my family home. HVAC topics can be tricky for homeowners so I decided to share my knowledge on the subject. When I am not working on DIY projects, you can find me at the beach or my local coffee shop.