Why is My Window Air Conditioner is Leaking Water?

If you’re lucky enough to have a window air conditioner, but it’s leaking water, you may be asking yourself, ‘why is my window air conditioner leaking water?’

A few issues could cause the problem: a clogged drain line, a drain pan leak, incorrect installation, freezing evaporator coil, or low refrigerant level. If your window AC unit experiences any of the above issues, it will leak water.

Luckily, troubleshooting these problems is easy enough. However, some might require you to consult with an HVAC professional. But before then, read this article to the end to know how you can identify the cause of the AC leaking water and the best way to fit it.

Reasons why your window air conditioner is leaking water

People always have lots to worry about when it comes to the heat, especially during summer. Sometimes, this could mean having a window air conditioner installed in your room or house during this sweltering season. While it is helpful, you should also know that air conditioning units are prone to leakage that can cause serious damage if not treated immediately.

You want to address the leakage early to reduce the risk of water damage to both the air conditioner and your home while also improving efficiency. But where do you start? The best place to start is identifying the problem causing your air conditioner to leak water before fixing it.

Here are the common causes of window air conditioner leaking water and their best fixes:

1) Clogged window air conditioner drain line

Windows air conditioners work by drawing in hot air from the room, cooling it down, and releasing the cool air back into the room. As the air is cooled, water vapor condenses on the coils and drains out of a tube or hole in the bottom of the unit.

This tube or hole is called the condensation drain. It is usually located on the side of the unit. The purpose of the drain line is to remove condensation from the air conditioner. If the drain line becomes clogged, it can cause water to leak inside or outside of the unit.

The clog or blockage can be caused by all the dust and dirt accumulated on the coils over time. Insects and animals such as bees and spiders can also facilitate clogging. And guess what; when the drain line is clogged or blocked by all the above stuff, the water will back up, filling the drain hole and eventually the drain pan. In return, it will find an alternate route that will make the air conditioner leak water.

How to fix it:

The solution here is to clear the clog by cleaning the drain line. Typically, this is an easy fix. Get yourself a drain clog remover and some vinegar. You might need a screwdriver to open the front cover of your dehumidifier and gain access to the drain pan.

Pour some vinegar on the drain pan and in the drainpipe (if you have one) and allow it to sit for a few minutes. Insert the clog remover into the drain pipe and rotate it to remove anything blocking the condensate pipe. Pour some water on the drain pan and watch if it’s flowing out.

2) A Leaking Hole or Crack on the Drain Pan

With the drain pan responsible for collecting the condensate water falling from the evaporator coil, if compromised, it can cause your window AC to leak.

If your drain pan has a hole or a crack, it can leak water. One possible cause of the crack or faultiness is a manufacturing defect. It can also be that the drain pan was damaged during installation or servicing; a sharp object, such as a nail or screw, can easily puncture the drain pan.

Rust and corrosion in old models can also eat away a section of the drain pan and create an alternate passageway for the condensate water.

How to fix it:

While you can fix a metal drain pan by taking it to a welding shot, I wouldn’t recommend it. The best option would be to get a new drain pan for your window air conditioner. If it’s a tiny hole on a plastic drain pan, get a plastic hole filling adhesive and use it. If it’s a crack, replace the drain pan entirely.

3) Frozen Evaporator Coil

An air conditioning system’s evaporator coil is a heat exchanger that takes heat out of the enclosed room and deposits it into the refrigerant flowing through the coils. In other words, your evaporator coil is what makes air conditions work. And if you have a window or wall-mounted AC unit in your house, then you have an evaporator coil.

The evaporator coil can strip heat from the room air as the cold refrigerant passes through it. But as it’s doing so, the air moisture is condensed from vapor to liquid water. The water drops down the fins into a drain pan.

However, at times it can freeze and cause ice to form. As the ice melts, it can melt too fast; filling the drain pan can cause a leak, or it might be so big that it’s melting outside the drain pan.

a) Cold Weather

When the outside temperatures are below a certain point, the evaporator coil can freeze up. And if enough ice water forms before it defrost, the water can drip outside the drain pan, causing the unit to leak water.

b) Low Refrigerant Levels

The same issue can happen if your unit’s refrigerant levels are too low. Typically, the refrigerant is supped to change state, liquid to gas and vice versa, to help with the cooling. If it’s too low, the air conditioner won’t be able to operate and instead, the evaporator coil will freeze up and cause the unit to leak water.

c) Refrigerant Leak

If your air conditioner is old, the refrigerant passage is leaking. A refrigerant leak can cause freezing at the leaking point, increasing the air conditioner’s chances of leaking water.

d) Clogged air filter

The air filter is responsible for capturing air impurities before reaching the evaporator coil. It’s supposed to keep the air clean, but in the process, it collects a lot of (dust, pollen, dirt and more) particles that can clog it and restrict the airflow. The evaporator coil can freeze without enough airflow and cause the Ac to leak water.

How to fix it:

The best solution here is to run the fan only and allow the ice to melt. You will also need to monitor the outdoor temperature and compare it with your unit’s optimal operating temperature level.

You can install a thermostat to check it for you. If it’s caused by low refrigerant levels or a refrigerant leak, get an HVAC professional to have a look.

Don’t forget to remove the air filter and give it a nice clean. If it’s too dirty, consider getting a new air filter to replace it. That will prevent the evaporator coil from freezing and improve the air quality.

4) Improper Installation

Window air conditioners can typically be installed in the window itself or through the wall. It must be level to ensure the condensate drops on the drain pan and flows through the drain hole. A slanting installation can cause the water to gravity drain to where the window air conditioner is slanting.

Assuming you did a DIY installation and forgot to check how to level the unit and the AC slanted toward the inside of the house, the water might start to drip as soon as the first hours of operation. The same can happen if the AC slants toward the outside. That could even be worse if it’s slanting too much that the water leaks to the electrical components.

How to fix it:

You want to get a level and measure how much the air conditioner is slanting from all angles. You want to make sure it stays level on all sides. If it’s becoming tricky to make it level, calling an HVAC professional to help out is the option. Avoid drilling and hole to act as a substitute. Window AC units have a specified build, and altering can void your warranty or cause more problems

Related Questions

Is a window air conditioner worth it?

It depends. Window air conditioners are a great way to cool a single room, and they’re much cheaper than central air conditioning. However, they don’t work as well in hot weather, and they can be quite noisy. If you live in a climate where the summers are moderate or cool, a window air conditioner is likely a good investment. If you live in a hot climate, you may be better off with central air conditioning.