How Often Should AC Air Filters Be Changed

How Often Should AC Air Filters Be Changed

Air conditioners are primarily cooling machines. However, they also have another valuable function that increases your comfort at home. Your hardworking central AC not only cools your home but also improves the air quality inside it.

As air passes through your AC system, dust and other impurities are caught in the air filter, which means that the air cycling back to you is clean.

With continued AC use, your filter will accumulate all the impurities in the air, which can cause a lot of issues for you and your unit if left unchecked. It’s important to change your air filter regularly to maintain good indoor air quality and efficient AC function.

How often do you need to change your AC Air filter? It depends on a lot of factors. First, let’s find out more about air conditioner filters.

What do filters do for your AC?

Air filters in central air conditioners can be found inside the filter chamber, which is typically near your AC’s air handler. It usually comes in the form of either fiberglass or pleated paper or cloth inside a hard cardboard frame.

Air filters catch all kinds of particles like dirt, dust, smoke, mold spores, lint, fur, dander, pollen, and so much more. Air filters can also take out harmful chemicals from the air such as formaldehyde, ammonia, and benzene.

Air filters ensure that only clean air cycles through your unit. Thus, the AC’s sensitive inner parts are protected, and you get to breathe clean and cool air.

Air filters are important parts of your AC. A lot of problems with air conditioners can be traced back to a dirty and neglected filter. Oftentimes, you’ll find that issues like slightly diminished cooling can be fixed by a simple filter change.

Even without any issues arising, it’s best to regularly replace your air filters anyway to make sure that your AC runs smoothly and your home indoor air is healthy.

How often should you change your AC Air filter?

It depends on the air filter itself. The basic 1 to 2-inch pleated air filters can last anywhere between 30-90 days. 3 to 4-inch filters can last around 6 months. The thicker your air filter is, the longer it can last.

You can also take a look at your filter’s MERV (Minimum Efficiency Reporting Value) rating, which determines its effectiveness in filtering out particles. When buying an air filter, make sure to get one with your AC manufacturer’s recommended MERV rating to maximize its filtering effects. The higher the rating, the better the filter’s capabilities are.

However, do not use filters that exceed your manufacturer’s maximum MERV rating, or you may end up damaging your unit. Better filtration means smaller holes or pores, which can strain the air flow through your AC and impair the unit’s efficiency.

It’s best to check with your AC manufacturer or ask a licensed technician what the best MERV rating is for your AC filter.

The filter type and rating aren’t the only factors you need to consider when it comes to scheduling AC filter changes. There are many other reasons you may need to change more often. Here are some to watch out for:

Air Conditioner Usage

As you use your AC, more and more particles get caught in the filter. If you use your air conditioner for longer periods, you may need to change your filter much more often. If your air conditioner is not frequently used or is in a vacation home, you only need to change it 1-2 times a year.


If you have any pets, their fur and dander can get caught in the air filter and clog it faster. If you have any furry friends at home, it is recommended to change your filter every 60 days. Although, you may need to change your filter more often depending on how many pets you have or how much they shed.

Allergies & Respiratory Issues

Air quality is extremely important to those with allergies and other respiratory issues. Those with health issues need to have the least amount of dirt, mold, fungi, pollen, dander, and other allergens in the air as possible. If you or your family have allergies, it is best to change your AC filter every 20-40 days instead.


Is your house located in the middle of a bustling city? Is it in a desert area? Do you have a smoker at home? These factors can make your AC filter get dirtier faster. If your environment exposes you to more dirt and dust, it’s best to replace your air filter more frequently or at least every month.

Size of Home

You may also need to change your filter more often if you have a big house since a larger home will typically have more fabrics that shed lint and more things that can accumulate dust. That means your AC has more air to clean and more particles that can get caught in the filter.

How to tell if it’s time to change your filter

Some warning signs tell you when it’s time to change your air filter. The very first way to determine is the length of time since your last filter replacement. Based on your home and health condition, check if your filter has been changed in the last 30 to 90 days. If you can’t even remember how long ago it was, it’s probably time for a change.

Another sign that your filter needs to be replaced is the presence of more dust in your house. This is due to your air conditioner cycling back the dirt and dust that enters its system. You may also notice dirt accumulating near your AC vents

Dust is not the only thing that can be cycled back into your home. When the filter is dirty, you may notice allergies flaring up as pollen, dust, and other allergens also get released back into your home.

If you run your AC for a long time with a dirty filter, this may cause drain pipe clogging and mold growth. A musty smell coming from your air conditioner is a big sign that you need to change your filter and clean your unit too.

Another symptom of a dirty air filter is an air conditioner that isn’t cooling as effectively as before. If you notice this problem, check your filter right away and change it if it’s dirty. This can solve the problem before it becomes bigger.

You may also run into issues with higher electricity bills. A dirty and clogged air filter makes it hard for your air conditioner to operate. If your AC is having a hard time, it uses more energy to cool the air in your home, leading to a sudden spike in your bills.

Another thing to look out for is if your air conditioner is hot to the touch. Check the back unit if it’s hotter than usual or if it’s blowing hot air. This may be a sign that your AC is straining and working overtime to provide cooling for your home due to a dirty filter.

In the end, a simple visual check is still the easiest way to find out if your AC filter needs a change. Just pop open the air filter chamber and check if the filter is dirty. When you install a new filter, it’s best to check it every week to monitor how fast your filter gets dirty. This way, you can work out an accurate replacement schedule.

You can replace your air filter yourself, but you can also call a company that provides AC Maintenance. They will not only replace your filter but also do a general cleaning and check-up of your AC.

Why is it important to change your AC filter?

Changing your air conditioner’s air filter regularly is a must if you want your air conditioner to last a long time. Doing so prevents any dust or particles from entering the air conditioner and damaging its inner parts like the compressor and coils.

A dirty filter also makes your AC work overtime, which can lead to the faster degradation of your air conditioner’s fans and eventually the whole unit itself.

It’s also important to think about your and your family’s health. Anything that the filter doesn’t catch will simply re-circulate around your home. A dirty filter also causes internal mold, which can lead to the AC blowing spores out into the air you breathe.

The simple process of changing AC filters saves you money in the long run. Your AC lasts longer, you save on bills and repairs, and you save on health expenses.

It might seem like a tedious task that you want to put aside, but you should prioritize it to avoid bigger problems down the line.

CPI Plumbing, Heating, and Cooling Services

Is your air conditioner not running as efficiently even after a filter change? It might be due for a maintenance session. Call Skagit County’s trusted plumbing and HVAC experts now!

CPI provides high-quality AC repair, replacement, or maintenance services in Mount Vernon, WA, and surrounding areas.

You can also avail of an HVAC service agreement with us and arrange a maintenance plan that’s right for you and your home.

Call us now at (360) 822-9306.

Our team of experts is ready to help you with all your plumbing and HVAC needs.

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