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How Do I Know If My AC Filter Is Dirty? 6 Signs To Look For!

6 signs your AC Filter is dirty. And, what can go wrong when it is. Plus, homeowner tips about AC filters & your homes air quality overall.

How Do I Know If My AC Filter Is Dirty?

The most obvious way to tell if your AC Filter is dirty is visual. Open the vent door and have a look. If it looks obviously dusty and dirty, you should replace your AC filter.

There are also some less obvious signs that your AC filter is dirty.

Image of someone cleaning an AC Return Air Vent with a vacuum for a post about signs that your AC Filter Is Dirty and loud air return vents.

5 More Signs You Have A Dirty AC Filter

  1. If your home is dustier around the air vents, you might need to replace your filter.
  2. Like I mentioned in the video above, if your air filter is louder than normal, it’s probably dirty.
  3. If someone in your home is having allergy problems indoors, you might need a new AC filter. Allergen Air Filters are the best at removing allergens and cleaning the air in a home.
  4. Your Air Conditioner is hotter than normal (overheating).
  5. Or, your Air Conditioner lines are freezing.

A dirty AC filter can cause expensive damage to your HVAC system. It can also allow dirt, dust and allergens to build up in the ducts. And, the air quality in your home can get pretty bad.

Check out What Happens If Your AC Filter Is Dirty? Can Your AC Stop Working to see more about the 7 ways that a dirty AC filter can negatively effect your home.

Here’s answers to a few more common questions about AC filters.

Why Is My Air Return Loud?

A dirty air filter is one of the most common reasons that your Air Return is louder than normal. The air return pulls air through the filter.

If the filter is clogged with things like dust, dirt, dander and hair, then the air flow has been blocked. That blocked air flow can create extra suction on the back of the filter, producing an annoying, loud sound.

Watch this short video to hear the sound my dirty AC filter made in my Return Air vent.

YIKES! Here's How to Fix a Loud AC Return Vent - AKA The Noisy Air Vent!

Can I Vacuum My AC Filter

No, you can’t vacuum a disposable air filter. A vacuum wouldn’t be able to remove all of the dirt, dust, and allergens stuck between the fibers on the air filter.

A vacuum might also damage the air filter. The shape and spacing on the air filter is critical to it working effectively. So, it needs to be handled with care.

Here I am vacuuming the grill, aka Return Air Vent Cover. Most disposable AC filters can’t be vacuumed clean.

When you are changing the air filter, you can vacuum behind the air filter, around the frame, and the return air grill or vent cover.

There are some washable air filters that can be reused for a certain period of time. Those washable AC filters can vacuumed before cleaning, per instructions on the filter.

Electrostatic air filters are often washable. Be sure to read the reviews and description when picking a washable air filter.

When you change your Air Filter, vacuum inside the return air vent to keep your HVAC system clean.

How Long Do Air Conditioner Filters Last

Most disposable air filters last between 30 and 90 days. Check your air filter for the recommendations for how often to replace the air filter.

Some homes might need to replace their air filters more often than the recommended guidelines.

If you have pets, live in an area with poor air quality, smoke, have bad allergies, have carpeting, or if have a lot of people living in your home you probably need to replace your air filter more often.

Check out Amazon’s highest rated air filters here, for affordable options you can have delivered to your house.

Image of someone cleaning an AC Return Air Vent with a vacuum for a post about signs that your AC Filter Is Dirty and loud air return vents.
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Can I Run My AC Without A Filter

No, you can’t run your AC without a filter. If you do, your AC will be pulling dirt, dust, hair, and allergens into your HVAC system.

Running your AC without a filter can reduce the lifespan of your HVAC system, cause costly repairs, or deposit dirt in the duct work.

Leave your dirty AC filter in place until you have a clean filter ready to replace it.

Read Best AC Filter Replacement for Cleaner Air in a Home for everything you need to know about MERV ratings for AC filters and how to pick a filter that is safe for your HVAC system AND which filters clean air the best.

Well, that’s it for What Happens if your AC Filter is Dirty!

More DIY Posts For You

Feeling inspired? Now that you know what happens if your AC filter is dirty, go change that air filter!

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