Why Is My Window A/C Leaking Water?

Why Is My Window A/C Leaking?

A window A/C unit is a great way to cool a room and make things comfortable. But, when your window A/C starts to leak water, it can signal trouble.

It’s normal for a window unit to leak outside a bit; water that collects during regular operation needs to go somewhere. But if the leak is continuous or leaking inside your home, this signals a bigger problem. It could be dirty or damaged filters, broken internal parts, clogged drain holes, or an improperly installed unit.

Your first step is to determine the potential cause of the leak, narrowing down the possibilities. Some reasons you can likely remedy yourself, such as changing the filters, while others will require a professional. In some cases, you might find you need an entirely new unit.

My Window A/C Unit Is Leaking Outside

If your window unit is occasionally leaking a small amount of water outside, this is normal. As your A/C runs, water collects in the bottom of the unit over time.

This water needs a place to go and typically drips out through a drain hole that leads outside. In other units, there may be another way that the appliance gets rid of the excess water.

The critical factor here is the amount and frequency of the water outside below your unit. If it is occasional and not forming large puddles, you are in good shape. However, if a large pool of water starts to form below the unit, this indicates a bigger problem.

Likewise, if you notice a constant stream of water coming from the unit, there’s an issue.

My Window A/C Unit Is Leaking Inside

You should never experience water leaking inside of your home from your window A/C. If this is happening, you need to pinpoint the problem ASAP and resolve it. Likewise, if you notice continuous leaking from your A/C unit outside.

It’s also essential to mop up any puddles on your floors and place a bucket under the leak. You want to prevent any further damage to your floors while you work on the repair.

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Here are the most common reasons for a window A/C leaking water inside the home (or excessive leaking outside).

1. A Dirty Unit Or Dirty Air Filters

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It’s good practice to clean your window unit’s air filters every six months. These filters catch dirt and debris before they go into your unit. But, if the air filters get dirty, they can’t filter.

Over time, this can lead to your actual unit becoming dirty too. It also leads to ice building up inside the A/C, and when it melts, it leaks onto your floor.

How To Fix It

You need to either clean out your A/C yourself or have the unit professionally cleaned and serviced. If necessary, you may need to get a replacement air filter as well. Then, remember to clean the filter every six months.

2. A Clogged Drain Hole

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Another thing to add to the top of your troubleshooting checklist is the drain hole. It’s typically a small hole in the back of the unit, designed to allow water to flow outside from the A/C. But, if it gets clogged with dirt and other debris, the water will start to leak out elsewhere.

How To Fix It

Inspect the drain hole for any obvious clogs, like mud, leaves, etc., and if you see any, remove them. This is likely the cause of your leak if you find these items blocking the hole, and it should fix the problem.

But, it’s also very likely that your unit does not have a drain hole. Instead, most window units have a slinger ring.

This is a fan that gets water from the drain pan and tosses it against the coils. It has a two-fold purpose of reducing heat on the coils and water in the pan.

Other window units might have a drain plug. This design allows the unit to hold water until it is serviced, and a technician can remove the water. If your unit has a drain plug, you can remove it to let the water drain out.

But, no matter what, you should never drill a drain hole in your unit. Instead of helping, it could lead to permanent damage. Also, it could void any warranty that you have in place on the appliance.

3. Blocked Drain Pipes

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There are usually a series of pipes bringing water to the drain pan. You can check them for clogs. If you’re dealing with a severe blockage, water can start leaking from your unit. 

How To Fix It

Although it could be relatively simple to clear the pipes, it’s best to call a pro to handle these blockages. You don’t want to risk any further damage to the A/C’s internal parts.

4. Frozen Evaporator Coils

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If the evaporator coils start to ice up, it can cause the drain pan to overflow and leak water. A few things can cause your coils to freeze, including low refrigerant levels and cold temperatures.

How To Fix It

Stay on top of your coolant levels, replenishing as needed. Some new models have a display that shows the refrigerant status. But, having your unit serviced regularly is also a good way to keep your coolant at an optimal level.

If it’s under 60 degrees outside, try opening up some windows to cool the home instead of running your unit constantly. This can help prevent the coils from freezing, and it will save you a few bucks on your energy bill.

5. A Damaged Drain Pan

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There is a drip pan toward the back of your A/C unit. It catches the condensation the AC makes while it’s running. The drain pan is a vital component of your A/C because it keeps this water from dripping everywhere.

Typically, you can leave the drain pan alone as there shouldn’t be too much water collecting in it at one time. Natural evaporation should be able to take care of it. But, if the drain pan is rusty or damaged, it’s another story.

How To Fix It

All you need to do if your problem is an old, broken drain pan is get a new one. You can switch it out yourself or hire a pro if you prefer.

6. Broken Or Damaged Condenser Pump

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A main component of your window A/C is the condenser pump, ensuring water goes in the right direction. But, like many things, over time, it can get dusty and dirty. If you have an older pump, it’s susceptible to more damage and breaking.

How To Fix It

Check the pump, and if you notice dirt and clogs, drain it and let it soak in soapy water. You can also make sure any connections to the pump are clear and clean. Let the pump dry thoroughly, then put it back in the unit.

If upon inspection, the pump has damage, you need to replace it. However, if you’re dealing with a broken pump, replacing the entire window unit might be a better idea.

7. Someone Installed The Window A/C Unit Incorrectly

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Whether you installed your window A/C unit or you had a pro do it, mistakes can happen. If your unit is leaking and it’s brand new, it may be due to poor installation. It’s critical for window units to align within the window frame properly; otherwise, they can leak.

Another vital part of the installation process is sealing around the unit appropriately. Professionals know how to do this the right way and the right amount of sealant to use. If there is an insufficient seal, it allows in too much hot air, leading to excess moisture and leaking.

How To Fix It

Your best bet in this situation is to remove the unit and reinstall it. But, call a professional to do the job. If it was a pro that did it in the first place, you might want to try someone new.

Frequently Asked Questions

Why is my window A/C unit spraying water?

If you feel water droplets hitting you when you near your A/C unit, this isn’t typical. What’s likely happening is the drain pan is full, but the unit is improperly aligned. Therefore, the water starts to overflow the pan, and as it moves, it can spray out through the vents.

You’ll need to realign the unit and pan. It might require reinstalling the unit; call a pro to make sure.

Something is leaking from my window A/C, but it’s not water. What is it?

Your AC could possibly be leaking refrigerant; if so, you’ll likely hear a hissing sound accompanying the leak.  You’ll also notice a difference in your unit’s performance. If you keep having issues with leaky refrigerant, it’s time to consider a new unit.

How much is a new window A/C unit?

You can get window A/C units in various sizes and models and with a wide range of features. For example, some A/Cs feature remote control capabilities and higher efficiency ratings. Typically, you can pay anywhere from $150 to $1,000, with the most significant determinant being the BTUs.

For the installation, plan to add another $50 to $200 depending n the scope of the project. It can take anywhere from two to four hours, and pros usually charge an average of $40 per hour.