HVAC professionals are often asked: How often should you change HVAC filters? Being a property owner is not an easy undertaking. But there is one task many property owners ignore: keeping the HVAC system up to standard. If you’re unsure how or why to do this, you have come to the right place.

An essential element in maintaining any HVAC system is regularly changing the HVAC filters. Perhaps you have an HVAC system in your home or business. If so, you should be replacing your HVAC filter every 90 days. And if you have allergies, pets, or babies in the space, you’ll need to change the HVAC filters more often.

If you haven’t replaced the air filter in a while, your system is likely working under heavy stress. Unfortunately, the air quality inside your home or office is unhealthy, and your energy bill is likely off the charts.

With the help of our guide, you’ll learn everything there is to know about an HVAC filter. We’ll cover what it is, why it is so essential, and the side effects of skipping this task. But, most importantly, this article will answer the question: How often should you change HVAC filters?

How Often Should You Change Hvac Air Filters

What Is an HVAC Air Filter?

The filters used in HVAC systems, furnaces, and AC units are usually made with spun fiberglass. These are the same kind of materials used in attic insulation. And these filters are installed in a specific section of the unit.

An air filter acts as a barrier. It prevents dangerous pollutants, dust, and dirt from getting into your HVAC system and the air inside your property. In addition, these filters are designed to trap pet hair, mold, bacteria, lint, and more.

But if you fail to change your filter regularly, all those accumulated contaminants will ruin your system. They’ll likely also harm your personal health.

What Is a Minimum Efficiency Reporting Value (MERV) Rating?

All HVAC filters have a MERV rating or minimum efficiency reporting value. From 1 to 16, this number determines the size and type of pollutants it will trap.

When you turn your HVAC system on, warm or cool air will circulate through your home or office. And it will regulate the temperature according to your presets. The filter traps and collects dirt, dust, and other allergens as the air starts moving, improving indoor air quality.

The MERV number indicated on the filter’s packaging indicates how well it will get rid of these contaminants. In addition, it indicates how well the air filter deals with all sorts of airborne contaminants.

Therefore, filters with a higher MERV rating work more efficiently than those with a lower rating. HVAC filters with a MERV rating of up to 16 are ideal for residential and commercial use. However, remember that just because the filter has a higher rating does not mean it is better.

Check your HVAC system’s user manual to know which MERV rating the manufacturer recommends. Using a different one could jeopardize your unit’s integrity for the intended space.

Why Is It Important to Change an HVAC Air Filter?

HVAC filters are among the most critical components of an HVAC system. Despite that fact, it is often neglected by property owners. They do so much more than just filter allergens and improve the air quality inside your home or place of business. They are also the first line of defense against larger objects traveling through the vents.

For example, pieces of insulation without an air filter could damage your HVAC system.

If you don’t change the HVAC filters in your HVAC system regularly, they will turn against you. A clogged air filter is the number one reason causing broken HVAC units. This is because all the air pumped by the system will pass through the HVAC filter, accumulating all the natural airborne pollutants.

As the filter continues to catch dirt, dust, pet hair, or mold, it’ll create a layer that’ll grow thicker and thicker over time, eventually preventing the air from passing through. Therefore, replacing the HVAC air filter is a task you should never ignore.
It will help keep your energy bill low, the air clean, and your system operating efficiently. Unfortunately, this is a task most property owners tend to neglect. If you are one of them, now you know better.

What Is A Merv Rating

How Often Should You Change HVAC Filters?

There is no straightforward answer to the question: How often should you change HVAC filters? The manufacturers recommend you change them at least once every three months. However, as experts in the field, we can tell you that the answer will depend on several factors.

General Recommendations

Elements such as the weather in your region and the number of people using the property play a role. Whether you have pets or not is also among the things to consider. But one of the primary factors is the type of filter your unit uses.

Cheaper fiberglass models should be changed once every month. This is because they have a low MERV rating, so they aren’t great at “filtering” allergens. On the other hand, if your unit uses a high-end plated model with a MERV rating above 12, you should replace them every six months. But these estimations are still influenced by the factors mentioned above.

Even if your unit uses high-quality filters, professionals recommend you have them changed every 90 days. This is because a higher MERV rating means they trap more particles, so the filter’s efficiency decreases quickly over time. Below is a complete list of all the factors to consider with answering the question: How often should you change HVAC filters?

Allergies or Other Breathing Issues

If you or someone in your family suffers from allergies or asthma, it will affect how often you should change the HVAC filters. Failure to change the filters makes you more susceptible to all the allergens polluting the indoor air. If this is the case, change the filter every six weeks to ensure the indoor air quality remains high.


Another factor that determines how often you should change HVAC filters is pets. You know they shed loads of hair if you own any cats or dogs. And some of it will end up in the HVAC filter. So in this instance, you should replace the filter every two months.

Young Children or Babies

If you’re the proud parent of a growing toddler, you must ensure the air they breathe indoors is clean. How often should you change HVAC filters if you have kids in the house? Every 2 to 3 weeks should be enough to maintain optimal air quality year-round.

HVAC System Uptime

How long you have your system running each day will directly affect how often you should change HVAC filters. For example, perhaps you live in a place with a moderate climate, and you only use your HVAC system for a few hours a day. Then a single high-quality air filter should last you from an entire season to a year.

However, what if you live in a place with complicated weather conditions and your unit has to be on nearly 24/7? In that case, you should replace the filter at least every 2 to 3 weeks.

The Size of the Building

Do you live in a big or tiny building? The size of your building will determine how often you should change HVAC filters.

HVAC systems in smaller properties need to pump less air to regulate the temperature. This means you won’t have to replace the filter that often. However, some HVAC systems installed in smaller buildings use a smaller air filter. And this will need to be changed at the same frequency as those in more extensive properties.

Air Quality In & Around Your Property

Another thing affecting how often you should change HVAC filters is the air quality inside and outside your property. Having pets or living near a beach or desert will require changing the HVAC filter more frequently.

Things to Look Out For: How Often Should You Change HVAC Filters

Regardless of how often you use your HVAC system, dirt will get trapped in the filter. After all, that’s the primary function of the HVAC filter. So, how do you know if your HVAC filter needs an urgent change? Some visual signs could help you determine if you need to change the HVAC filter as soon as possible.

Maybe your HVAC filter is only covered with a thin layer of dirt, and you can still see the filter’s material under it. Everything is good for now, and you don’t need to worry about changing the HVAC filter yet.

However, anything beyond that, you should have your HVAC filter replaced immediately. If you see a thicker and darker coating covering the entire filter, it’s time to act. This means that the filter has probably been in your HVAC system longer than it should have.

As a savvy property owner, you should check the filter every two weeks. This way, you can monitor the level of dirt, dust, etc., accumulating on the filter. And over time, you’ll be able to determine the estimated average shelf life for your HVAC filters.

If you encounter a musty smell or a thick layer of dirt, you know it’s time to change the HVAC filter. And should you have doubts, do the intelligent thing and change the filter irrespective. They aren’t expensive. And that small act could help you keep your HVAC system working correctly and save you thousands in bills.

Frequency To Change Air Filter

The Effects of Not Changing Your HVAC Filter

The blower fan inside the HVAC unit will have to work harder to regulate the temperature. This “overdrive” causes the HVAC system to draw more energy, thus, increasing your monthly electricity bill. Also, all this extra work will significantly reduce its lifespan.

The system will be unable to pump the air through the filter efficiently. This means that not every area of your interior space will get the necessary air to maintain the temperature. And you won’t be as comfortable as you should be in your home or office. As a result, the temperature sensors won’t register the preset temperature needed to signal the HVAC system to power down. And once again, that means higher energy bills.

The warm or cool air can’t travel through the HVAC filter as quickly and efficiently as it should. Therefore, the HVAC system is in danger of overheating or freezing up. Your system will consume more energy trying to regulate the temperature.

The HVAC filters’ material can quickly gather moisture once they get clogged. This creates the perfect environment for growing something detrimental to your health, like mold. Not only does this increase the bacteria present. It also makes it more difficult for air to circulate freely through the air filter if left unchecked.

But the air quality inside the building will be significantly compromised. And if mold makes it into the HVAC system, it will create much more severe and expensive problems for you.

The air won’t circulate as quickly as it should when the filter is dirty. Therefore, particles that would otherwise get stuck in the HVAC filter will travel freely through the building. Also, this build-up in particulates puts additional strain on your HVAC system. It’s far cheaper to regularly replace the HVAC filter than schedule an air duct cleaning every few months.

How Often Should You Change HVAC Filters Conclusion

Time to wrap up this article about how often should you change HVAC filters. Changing your HVAC filter on time is vital for many reasons. Not only does it help to maintain the AC unit, but it also prevents pollutants from entering your business or home. A clogged HVAC filter also strains the unit and could increase electricity usage. Therefore, replacing the HVAC filter on a regular schedule could save you on electricity costs in the long run. Thanks for checking out how often should you change HVAC filters.

FAQs about How Often Should You Change HVAC Filters

How do I know if I need to change my HVAC filter?

Often, you’ll see clear visual signs that your filter needs to be changed immediately. For example, look for dust and dirt accumulated in the intake and output vents. And note whether dust has accumulated over different surfaces around the house.

How long can I go without replacing the HVAC filter?

The longest recommended time you should go without changing the air filter is up to 90 days. However, if, for any reason, you are unable to change the filter after 90 days, it will not cause irreparable damage to your HVAC system.

What are the signs of a dirty HVAC filter?

There are some apparent symptoms of having a clogged air filter. This includes an increase in the amount of dirt and dust in the vents, noticeable loss in temperature, and noise coming from your HVAC system.

Does changing the HVAC filter make a difference?

Absolutely. Regularly changing the HVAC filter has a positive impact on your HVAC system. It will work as it should, keeping your interior space warm or cool and helping provide better air quality. In addition, your unit will work more efficiently.

What kind of HVAC filter should I buy?

Before making any purchase, you should check the user’s manual first. Some manufacturers offer recommendations about the type of filters you should buy for the unit. Look for pleated filters with a sturdy mesh and a higher MERV rating.

How often should I replace the HVAC filter if I have pets or small children?

According to recent studies, if you have small children living in the house, you should replace the air filter every other week. This will ensure the air quality remains high. Also, if you have pets like cats or dogs, it’s advisable to change the filter every three weeks.

What happens if I don’t change the HVAC filter?

The HVAC filters in your HVAC system are designed to trap big and small particles. This prevents them from getting into your unit and spreading through your building. If you do not change the filter, you risk irreparable damage to your system and personal health.

How do I change my HVAC filter?

Changing the HVAC filter in your HVAC system is a simple task that everyone can perform. Turn the unit off, unscrew the latch, remove the filter, and swap it for the new one.

What does an HVAC filter actually do?

The HVAC filters in your HVAC system are designed to trap all airborne contaminants like dust, dirt, mold, and other pollutants. The filters keep all these things out of your system and the air you breathe.

If I have allergies, how frequently should I change my HVAC filter?

People who suffer from severe allergy problems or asthma should consider replacing their HVAC filters at least once every two weeks. Maintaining good air quality is highly important under these circumstances.

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