Why Is My Window AC Leaking Water? Reasons and Solution

Why Is My Window AC Leaking Water

You will eventually come upon an air conditioner that is leaking water. What begins as a minor annoyance can quickly degrade ceilings, walls, and floors, not to mention the performance and efficiency of the air conditioner. Worse, mold can grow in damp environments and damage the air you breathe. And before you know it, your air conditioner has stopped working. Thedailysplash.tv will explain Why Is My Window AC Leaking Water and How To Fix it

why is my window ac leaking water

Window Air Conditioning Systems: An Overview

Window air conditioners are made to fit a range of windows, including left-to-right sliding windows and double-hung windows. Although most people understand that cold air is forced into your home while the exhaust is directed outside, it’s a good idea to grasp how a window air conditioner works before attempting to repair a leaking water issue.

When you peel back the shell of a window air conditioner, you’ll find that it’s relatively straightforward. Different models may have somewhat different looks, but they will all work in the same way. A set of controls and a grill with a filter are always present on the front. Warm air enters and passes through the filter before coming into contact with the evaporator coil.

On one side of the device, beneath the cabinet cover, you’ll discover a blower and fan. On the other hand, on the opposite side, there is a compressor. While the design and type of window AC unit you purchase will have different bells and whistles, most will feature a drain or drip pan to cope with excess water created by condensation.

Keep in mind that window air conditioners come in a variety of styles, including those with sling rings. Instead of emptying the water from the back of the system, they “sling” it onto the coil. Some of those models have drain plugs, while others don’t, so if you have a manual or know the brand and model, consult it before attempting to fix any problems with your unit.

Why Is My Window AC Leaking Water

why is my window ac leaking water

Water is leaking from the window air conditioner due to a clogged condensation drain

Water is leaking from the front of the window AC unit in 1 out of every 3 or even 2 situations due to a blocked condensation drain. Fortunately, this is the most straightforward cause of leakage.

Condensation drains are used to remove moisture from interior air by every window air conditioner (works like a dehumidifier). The condensation pan, which is placed at the bottom of the window AC unit, collects the moisture that has been removed. The overflow pan is connected to the drainpipe by the condensate drain, which allows regular operation.

The condensation drain is partially or permanently clogged, causing window AC leakage. The condensate drain can be clogged by anything from dirt, mold, leaves, or even dead creatures like bees. As a result, water is unable to escape from the condensate pan, resulting in a spillover. Water will drip (partial obstruction) or leak (permanent blockage) from your window unit on the inside or outside, depending on where the window AC is leaning.


The solution to a clogged condensate drain is simple. You must clear the obstruction. Locate the condensation drain by opening the backside of the window AC unit. If it appears to be clogged, use a thin object – a needle, toothpick, or thin screwdriver – to dislodge the obstruction by inserting the thin object into the drain and wiggling it around.

This is frequently the only thing you need to do. Check if the leak is rectified by turning on the window air conditioner. Even if the outside temperature is quite hot and there is a relative humidity of +60 percent, a window AC unit operating at 100 percent capacity should be able to drain the surplus water without issue.

Water Is Seeping Into The Condensate Pan Through A Hole

If your window air conditioner has been operating properly for more than ten years and is now leaking all over the place, you may have an issue with a damaged condensate pan. This type of water leaking is more common in older units.

The condensate pan catches the water that the window AC unit removes from the indoor air. This pan is found at the bottom of window air conditioners and has a capacity of fewer than two pints. In a properly operating unit, moisture collected there is transported to the drainpipe via the condensation drain.

why is my window ac leaking water

The condensate pan must be intact to prevent window air conditioner leakage. If there is a hole or a minor dent in it, water will begin to flow from that hole. Pan damage can result from an unintentional puncture during installation for newer units, as well as rusting and corrosion in older units that have previously worked perfectly.


There’s no getting around it; the hole or dent in the pan must be filled. If you can afford it, you can get a new condensate pan; they are reasonably priced (around $30). If you want to stop the window air conditioner from leaking, you can plug the space in the bottom of the window AC unit with water-resistant adhesive or resin.

You may need to close more than one gas in the condensate pan if you have an older device and the condensate pan is corroded. New holes will most likely form as a result of gradual corrosion, and you will have to address this leaking window AC problem multiple times.

Buying a new pan, or even a whole unit, maybe a better alternative in certain situations. As always, look for a window air conditioner with a high EER rating; the best energy-efficient window air conditioners may be found here.

The Window AC Unit Leaks Due To A Frozen Evaporator Coil

There’s a reason why air filters should be cleaned at least twice a year. Dirty air filters can quickly lead to a frozen evaporator coil. As a result, the window air conditioner will leak and perhaps blast hot air (instead of cold air).

The purpose of air filters in window air conditioners is to remove bigger particles such as hair, dust, bugs, and other contaminants. All of these contaminants, as we’ve seen before, can induce condensation drain leakage. The window AC unit will receive unrestricted airflow and perform correctly if air filters are cleaned or changed on a regular basis.


How clogged air filters cause leakage: The airflow across the refrigerant coil will be hindered if air filters are not cleaned (even up to 10 percent lower CFM might be problematic). The refrigerant coil is cold, and its job is to cool the heated air that enters the system. It will become gradually colder and eventually freeze over if it receives less hot air than predicted (due to the air filter’s restriction of airflow). When the ice melts, it can release up to a pint of water, causing your window air conditioner to leak.

How to clean clogged air filters (it’s not as simple as it sounds): Isn’t it just a case of ‘changing the filters’? The refrigerant coil is most likely still frozen if you already have leaks. The leak will be fixed in a few hours by changing the air filter, so bring your towel! During that time, the remaining ice will be leaking through the window air conditioner. Be near the unit until the coil is totally unfrozen and the unit stops leaking to avoid damage to furniture, walls, or carpet.

A frozen evaporator coil might cause major issues. Leakage is only the beginning; if you have been ignoring the leaky window air conditioner for a long time, further window air conditioner problems may arise in the future. Simply remain cautious and keep an eye on the device even after the leak has been resolved.

Coil Freezing-Melting Leakage Can Also Be Caused By Low Refrigerant Levels.

Low refrigerant levels are the worst of all the causes of water flowing out of the window air conditioner. The little leak can be readily repaired in the same manner as air filters may be. The bigger problem you’ll have to deal with is recharging the refrigerant. More information on how to recharge the freon in a window air conditioner may be found here.

The role of refrigerants in the operation of air conditioners is crucial. According to the 2nd Law of Thermodynamics, expanding and compressing this fluid creates the essential heat transfer that aids the air conditioning system.

Water leakage caused by low refrigerant levels: As refrigerant levels are reduced, the pressure inside the refrigerant lines decreases. The heat transfer capacity of the window air conditioner will be reduced as a result. The refrigerant lines will grow overly cold and finally freeze over due to a chain reaction. When they melt, the window air conditioner will leak water into the house (refrigerant coil is located near the indoor side of window AC).

why is my window ac leaking water


This may seem like a difficult chore, but with a little technical know-how, you can put freon in the refrigerant lines yourself. Simply follow the steps outlined in the article above, or contact an HVAC specialist for assistance. Just keep in mind that once you’ve refilled the freon and the unit is up and running again, the residual ice around the cold coil may melt, and you’ll need to be prepared with a towel if water begins to flow down the interior wall.

The Water Isn’t Being Pumped Out Properly By The Condensate Pump

This is only for homes have window air conditioners with condensate pumps that are installed below ground level. It’s one of the most uncommon reasons for indoor window AC unit water leaking; most people can safely ignore it, but if you have this identical arrangement, this information could be really useful.

The function of a condensate pump is if you have a below-ground air conditioner, it will normally come with an in-built pump. Instead of a drainpipe, that pump actively pushes the pooled water to the surface against gravity for proper drainage.

Water leaking caused by a condensate pump is easy to comprehend. The condensate pan will quickly overfill if the pump isn’t moving the surplus water to the surface, causing a leak.


This is likely the one item you won’t be able to do yourself. HVAC professionals should usually inspect built-in pumps. Every device is unique and includes a built-in pump that, if damaged, produces water spillage.

To avoid water from spilling all over your basement, an HVAC technician will most likely advise you to replace the condensate pump. Given the fact that these are built-in pumps, this isn’t a simple process.

Water Leakage Following the Installation of a Window AC Unit

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If you recently installed a new window air conditioner and it immediately began to leak, something went wrong during the installation. Leaking can be caused by a variety of factors, and it’s possible that leakage is the most obvious symptom of poor installation.

Remember that this could also apply if you’ve recently relocated an existing air conditioner to a different window.


It’s best to redo the entire installation process if your window air conditioner leaks water outside or inside the house in any event.

If the leaking persists after a new installation, the best course of action is to consult an HVAC installation specialist.

How to Repair My Window AC Leaking Water

One of the first things you should think about before getting your tools or water hose out is how long the unit has been leaking. Is it just this week that it’s been dripping, or is it a seasonal occurrence?

That’s crucial to remember because some homes have been struggling with dripping for years, while others may have discovered the problem overnight. It’s critical to keep an eye on the problem and respond swiftly, regardless of when the dripping began.

If you have carpet and a constant drop that you’ve dealt with seasonally for a few years, you can wipe away the water on hardwood or other exposed flooring surfaces. But if you have carpet and a constant drip that you’ve dealt with seasonally for a few years, the harm may already be done. If you have a leaking window air conditioner, it’s also crucial to consider where it’s located and who installed it.

Examine the Drain Hole

A little hole on the back of the unit is the most typical cause of a window air conditioner leaking water. It’s often known as a drain hole, and if it becomes clogged, water has nowhere to go. Depending on the temperature outside and how long it’s in use on a daily basis, this can cause it to drop water into your home quickly.

If there is a visible clog, look at the back or bottom of the unit. You may have a slinger fan or a system with a simple drain plug if you don’t notice a hole. Remove the plug if it’s plugged and let any water inside the drain.

Check manual

Consult your user manual if your sling-ring system doesn’t have a drain hole. But whatever you do, don’t drill a new hole in the bottom. It’s also worth noting that certain air conditioners require a small amount of water to function properly, so consult the owner’s manual if in doubt.

There are numerous discussions on the internet, as well as a few videos, claiming that drilling a hole in the bottom of your window air conditioner would help with drainage difficulties. That may be true in some circumstances and climates, but it is not a good idea. You risk damaging your Freon line or another component, which would be a costly mistake.

Remove any twigs, mud, or other debris that may be clogging the drain hole, and water should start to flow again. Even if there is no visible blockage, dirt and dust can clog the drain port over time. When using drain pans, all you have to do is remove the pan and empty it if it’s full. However, unless you have the improper type of system for your home or it is malfunctioning, you shouldn’t have to do this with newer devices.

Installation Error

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Was your window air conditioner installed over the weekend by you and a few friends or by a professional? If you choose to go the DIY route, that could be the issue, as poor window AC unit installation is a common cause of leaks inside. Installation is just as important if you’ve moved the device from one area to another. Weatherstripping, side retainers, and filler panels should all be checked on a regular basis.

More often than not, window air conditioners with a drainage system should be set slightly backward. You’ll want to refer to the manufacturer’s directions in this case, but a level will tell you everything you need to know. The problem is obvious if your eyeballs or a level tell you the unit is tilted forward and your window air conditioner leaks water.

Brackets and rails are one reason your unit may have slanted since you installed it. A safety lock may be installed on vinyl window systems, or the unit may be secured to the window sill with a couple of long screws. Make sure everything is in working order and that nothing needs to be replaced. Support brackets are the same way. Depending on the system, a minor modification to the bracket may be all that’s required to straighten out your window air conditioner.

For some of their systems, Frigidaire suggests tilting the machine at least 2 – 4 degrees downwards towards the outside of your home for perfect drainage. On LG’s 7,500 BTU unit, a 12″ bubble will be enough, whereas, on a few of their systems, GE advises a 1/3 bubble using a level. The point is to make sure there’s enough of an angle for water to flow backward rather than forwards and consult your manual if you’re unsure.

The Filtering System

This one is hit-or-miss, but we’ve heard lots of consumers claim that when they corrected this issue, their window air conditioner stopped leaking water. In any gadget, air filters or filters, in general, serve an important function. When the filter on your window AC unit becomes dirty, the system can bog down. Depending on the air quality in your home, this can happen quickly.

Air filters collect dust and particles when air is drawn into the system. And while it’s easy to forget to check them, it’s well worth the effort. Cleaning an evaporator coil isn’t cheap or easy. Therefore, it’s worth it to maintain it clean as a filter to avoid a number of issues down the road. Rust and other contaminants can accumulate in your system over time. So that a thorough cleaning may be necessary if everything else fails.

You’re now prepared to cope with a leaking air conditioner. Thedailysplash.tv attempted to demonstrate how, with the proper knowledge, you can quickly identify and resolve some AC dripping water difficulties.

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