Why Does My Window AC Sound Like Water Running

Window air conditioners can be excellent at helping keep our rooms cozy during the summer heat. However, these machines can sometimes become annoying, especially when they start to produce some noises such as water running. Why does a window AC sound like water running?

A window air conditioner may be producing the water running sound when the condensate drips from the evaporator coil, ice melting down as the evaporator coil defrosts, or water leaking from the drain pan. It could also be caused by a fault such as an object obstructing the blower fan or a broken part inside the AC.

If your window AC sounds like water running, those are the possible causes. If you want to know the exact cause and fix it, you will have to troubleshoot every problem stated above.

Common Causes of Water-Running Sound in Your Window AC

Even though window air conditioners produce some noise, some sounds can be annoying considering you’re sharing the same room. It can be as minimal as a hissing sound, water running, or even a loud cracking or banging sound.

When you start hearing these sounds, there is a high chance you will think your window AC is broken. Well, it doesn’t always mean that. At times, it could signify the air conditioner is working, or it could be a sign it’s going bad.

Since you’re reading this post, I’m assuming your window air conditioner is producing water running sound. If that is the case, don’t worry. You’re not alone.

Sometime back, I had a BLACK + DECKER Window Air Conditioner. One day I arrived home late, and my bedroom was too hot. I needed to start the AC to cool it down. But after 10 minutes, there was this sound (water running) coming out of the unit. I did not like it at all. And I was asking myself all sorts of questions, including ‘why does my window ac sound like water running.

The next thing I picked was my laptop, and I started searching for the solution. I didn’t find any helpful unit. I came across a suggestion in an AC forum. However, the suggestion did not work, so I had to find another solution. The idea that came up next was to sell the unit in the yard, get a new one and forget about it.

Little did I know I could (years later) find a better solution than selling the unit cheaply.

After long research, I found a solution. The list below gives you the common causes of water-running sound in your window AC:

Water dripping from the evaporator coil

As the air conditioner is busy cooling your air, it also dehumidifies the air. The evaporator coil condenses moisture in the air, forming water. The water then drops down into a drain pan. If your home air is too moist, the air conditioner will take out a lot of water.

As the water drops to the drain pan, it might create the sound of running water. You can confirm this by checking the amount of water dropping out of the drain hole. If it is more than normal, then that is the problem.

How to fix it:

The best solution would be to get a dehumidifier to remove the excess moisture in your home. And even though it’s a huge gamble, buying a dehumidifier can help you in a lot of ways, such as preventing water damage and mold growth.

Water melting down evaporator coil defrost

As the evaporator coil strips water from the air, it does freeze up at times. This can happen when there is not enough airflow or when the outside temperatures are too low.

The restricted airflow is caused by a clogged air filter, which happens when you stay long without cleaning it. The air filter cleans the air inside your home, and it will collect a lot of dust and other air contaminants. When the airflow is reduced, the evaporator coils get too cold, and ice starts forming, freezing it up. If the outside temperatures are lower than the indoors, there is a chance the evaporator coil will freeze up.

Depending on the freezing, the water from the melting ice can cause the sound of running water. You can expect it, especially when running the air conditioner low. One sign of a freezing evaporator coil is the window AC leaking water or fog forming around the vents.

How to fix it:

Start by allowing all the ice to meltdown by running the blower fan only. The next step will be cleaning the air filter to ensure enough airflow through to the evaporator coil. If it’s too dirty, replace it with a new air filter – it will help prevent the freeze up and better the indoor air quality. Don’t forget to make sure you run the air conditioner at its optimal temperature range to prevent freeze-up.

Water leaking from the drain pan

If your thermostat stays, the humidity and temperature are at the right range, and the air filter is all clean, but you’re still hearing the water running sound, the unit’s drain pan might be leaking. It’s easier to confirm this if your window AC’s drain pan uses its bottom cover as the condensed drain pan.

However, if yours has a separate drain pan, you will have to get your screwdriver kit and unscrew some screws to reach it. You want to look for a crack or a hole that causes the water to drip from other spots other than the drain hole.

How to fix it:

There is no easier way to fix a leaking drain pan than to replace it. You want to get yourself the right replacement by contacting your model’s manufacturer. If you can find a replacement or can’t fit it yourself, contact an HVAC near you to help you out.

Something is obstructing the blower fan

Air conditioners, including the window ACs, come with a fan that pulls air through the evaporator coil before blowing it out to the room. The fan rotates at high speeds to create enough vacuum to pull air into the unit and generate enough push.

If a light object such as paper gets stuck on the fan or near the fan so that it’s touching the outside of the rotating fan, it can create a water-running sound.

How to fix it:

Unfortunately, you have to take your window AC apart to reach the fan, and that might require more than the normal DIY skills. If you’re confident enough, you can use a Phillips screwdriver set, open the outer casing, remove the evaporator coil carefully to reach the fan.

Remember, there may be two or three items you will need to remove. So, it will require you to be extra careful and patient. If you feel you cannot pull it off, I recommend getting in touch with an HVAC professional.

A broken part inside the AC

If you can’t find the problem, there might be a broken part within the air conditioner shaking and producing the running water sound. You might have heard other sounds, too, like something cracking.

How to fix it:

At this point, the only option you’re left with here is to call a reputable HVAC technician to take the unit apart and figure out the source of the sound. The expert will have the right tools and expertise to diagnose your AC unit.

Related Questions

What is the normal window ac sound?

With the fan’s only moving part in a window air conditioner, you shouldn’t hear much, especially with all the fan noise deposited outside the room unless it’s running high. However, if you hear something, it should be a light sound that shouldn’t bother your ears.