Window air conditioner leaking: What it means & how to fix it yourself

Intensifying summer heat means that air conditioners spend more time running, which also increases the chance of problems. One of the most common issues homeowners face is a leaking window AC unit, which can lead to water damage, mold growth, and overall inefficiency.

Whatever you do, you don’t want to ignore a leaking window air conditioner, since doing so can exacerbate the problem and result in costly repairs down the line. But thankfully, you can diagnose and fix the unit yourself, without the need for an expensive service call.

If you find out that you need any replacement parts for your air conditioner while you’re troubleshooting, you can enter your model number at AppliancePartsPros.com to order them. Most orders arrive in just two business days, and we have thousands of free guides to show you how to install your new parts.

Important: The troubleshooting information provided in this article may not apply to your specific appliance model. While we strive to offer helpful advice for DIY appliance repairs, variations in models and configurations can lead to differences in troubleshooting steps, error codes and part replacements. For the most accurate guidance, we strongly recommend consulting the technical sheet for your specific appliance model.

Safety precautions

When working on any appliance, remember to keep safety first. Here are some tips to keep in mind:

• Always power off and unplug your appliance or switch off the circuit breaker before you attempt any maintenance or replacement work. This keeps you safe by eliminating any risk of electric shock.
• If the appliance has recently been used, give it plenty of time to cool down before working on it.
• Take your time while working to prevent accidents and personal injuries. Rushing is the enemy of precision.
• Work in a well-lit area so you can see and access appliance parts.
• Keep your workspace free of clutter and other obstacles. Keep children and pets away from the work area.
• Never work on internal parts with wet hands. Make sure the work area is completely dry.
• Check the user manual to see if there are specific installation or safety instructions related to your appliance or replacement part.
• Be gentle when handling or removing parts. Excessive force might damage the appliance or cause personal injury.
• Wear insulated work gloves to protect your hands from sharp metal parts and debris.
• When working with wires, avoid touching any exposed wires or terminals. If you need to touch a wire, use a non-conductive tool or wear insulating gloves to prevent electrical shock.
• Always take photos or make a note of wiring terminals or other connections before disconnecting them to make reassembly easier.
• Don’t test live voltage with a multimeter if you’re unfamiliar with how to prevent short-circuiting.
• Consider wearing safety glasses and/or a dust mask when working with chemicals, dust or a large amount of debris to prevent irritation or injury.

Read more: How to get better air quality from your window air conditioner

How to troubleshoot the window AC

Follow these steps to find out what’s causing your window air conditioner to leak and how you can fix it yourself.

Step 1: Check the drain ports

1. Make sure the unit is unplugged from the power source.
2. Find the drain ports at the bottom of the air conditioner.
3. Use a stiff wire or a small tool to probe and clear any blockages in the drain ports.

If the ports are severely clogged, you may need to remove the chassis from the cabinet to access and clean them thoroughly. To remove the chassis, you’ll need to find and remove any screws or clips that secure the chassis to the cabinet, then carefully slide the chassis out of the cabinet.

Step 2: Check the cabinet seals

Inspect the cabinet seals around the edges of the air conditioner. Look for any signs of wear, cracking, or deterioration in the seals.

If the seals are worn, they should be replaced to prevent air leaks and water drips.

Step 3: Inspect and recaulk the cabinet if needed

Check the caulking around the cabinet, particularly at the edges and corners. Look for any signs of rust, discoloration, or cracking in the caulking.

Clean the affected areas and apply fresh caulk as needed to create a tight seal.

Step 4: Clean the evaporator coil

Find the evaporator coil, which is typically at the back of the air conditioner. If the bottom fins on the evaporator coil are clogged or bent, use a stiff brush or a vacuum cleaner to clean and straighten them.

Step 5: Make sure the unit is installed correctly

• Make sure the air conditioner is level from left to right. You can use a bubble leveler to see if it’s evenly installed.
• Pitch the unit so the rear is about 1/2 inch lower than the front to allow for proper drainage.

NOTE: In very humid weather conditions, some condensation and dripping on the outside of the air conditioner is normal. If the dripping is excessive, you can attach a drain pipe to the air conditioner to carry the water away from the unit.

Read more: How to Clean Your Air Conditioner the Easy Way

More for you

Thank you for reading! We hope this guide helped you get your window air conditioner working again.

If you have any other appliance repair needs or projects, don’t hesitate to explore our other troubleshooting guides and videos.

If you need replacement parts or some extra help with ordering them, grab your model number and head over to AppliancePartsPros.com, where you can chat with a pro, read our DIY blog and more.

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