Due to Hurricane Sally, our standard shipping time will be delayed and could take up to 2 weeks.

Why is my air filter wet?

Juice. Rain. The ocean. These are a few things that are supposed to be wet. We like when these things are wet. They make us happy.


Shoes. Gremlins. Your AC filter. These are things that are not supposed to be wet. We don’t like when these things are wet. They’re gross, smelly, and sometimes even dangerous.

I suppose that, since we happen to be an air filter delivery business, we’ll focus on the wet air filters for now. Maybe we’ll touch on gremlins too, but don’t count on it.

A wet air filter can cause a lot of problems, but there’s only one thing that makes your filter wet in the first place. We’ll explore why your air filter is wet, and we’ll definitely talk about how you can fix it. But we’re going to start with the problems a wet air filter can cause.

A wet air filter can cause a reduction in AC power.

Think of an air filter as your air conditioner’s nose. Its job is to bring in air while collecting nasty particles that could damage its lungs. Changing your filters is like blowing your nose. You have to get all that nastiness out before it clogs up your sinuses and makes you sounds like Janice from Friends.

If your air filter gets clogged up with moisture, it makes it more difficult for your AC system to “breathe”. This reduces its power by limiting how much air can cycle through the system at a time. It’s like running with a stuffy nose – you’re going to get out of breath way faster.

If it’s hot outside, this is going to be noticeable. If you usually keep your AC at 74 degrees, your system won’t be cycling enough air to make it feel like 74. It’ll feel more like 78. So, you’ll turn your AC down to 70. This means you’re spending more on your electricity bill for something that’s easily fixable.

A wet air filter can break your AC system.

This is where the analogy between an AC system and a runner breaks down. If you run enough miles with a stuffy nose, your lungs will eventually get stronger to account for that.

Your AC system, however, doesn’t have the same regenerative abilities as our bodies. It won’t get stronger – it’ll just break.


If you run your system for longer in order to get the temperature down with a wet air filter, you’ll put massive strain on it. It’ll keep going until something gives, which can translate to massive repairs. A new cooling unit can cost upwards of $5,000 to $10,000. Yikes.

Another problem caused by a wet air filter is short cycling. Your AC unit will cool until it senses that your home is at the right temperature. Of course, because your air filter is wet, it won’t be. The system will soon pick this up, and immediately flip back on. This constant switching between on and off is not only extremely annoying (WHIRRRRRRR *click* WHIRRRRRRRRR *click* WHIRRRRRRRRR, etc.), but it’s also very bad for your AC system.

Because your AC is a fairly large and interconnected network of air, refrigerant, and electricity, it requires a lot of power and moving parts to kick back up. Doing this too often creates wear and tear, and eventually something will break.

vPerhaps the biggest problem created by a wet air filter is a system freeze. The air in your AC needs to move in order to give the cooling unit something to do. If your filter is wet, that air can’t move fast enough. This might lead to a frozen freon or drainage pipe.

This effect is compounded by the cause of your wet filter, which is condensation on your evaporation coils. This water can get to places it’s not supposed to be. When it freezes, it expands. This will burst your pipes, spraying water and freon everywhere and making the next few days of your life considerably hotter and more expensive.

A wet air filter can cause mold growth.

Here’s a list of things that should be alive in your home: your family, your pets, and your houseplants. End of list. That’s it! No more.

Here’s something that absolutely should not be alive in your house: mold. Gross, smelly, slimy, dangerous mold. And if your air filter is wet, that’s exactly what you’re going to have.


Mold is not immediately dangerous, but if you let it fester, it can start to cause allergies, respiratory symptoms, and permanent lung and brain damage.

When your air filter gets wet, it creates the perfect environment for mold growth. Mold, as well as any other kind of fungus, can grow extremely fast and is very resilient. The only way to fix it is by replacing your filter and repairing the underlying cause of your wet air filter.

What causes a wet air filter?

A wet air filter is caused by a clog in your AC’s drainage system. When your freon is sent through coils to be cooled down, the pipes that make up those coils get very cold. This creates condensation, which needs to be drained somewhere.

Usually, it either flows down a drain pipe or drips into a pan, which is then connected to another drain pipe. The water drips down these pipes and exits outside of your house.


When this system works properly, the only side effect is a small, well-watered patch of ground outside your house. When it doesn’t work properly, the result is mold, broken AC, and lot of suffering.

To get it fixed, you’ll need to call an HVAC professional. If you know what you’re doing, you can probably fix it yourself. If you don’t know what you’re doing and you try to fix it, you could make it worse and even void your home warranty. Just get a professional.

After you fix the underlying problem, you’ll need to replace your air filters. This is where Filter King comes into your life. We have the best, most affordable air filter delivery in the world. Check out our online air filter store, find your size, and get your new air filters in just a few days.

We even have an air filter subscription service, so you never have to worry about forgetting your air filters. Air filters should be replaced at least every three months, and failing to replace them can cause major AC issues and bad air quality. Let Filter King take that off the list of things keeping you up at night!