A leaking air conditioner isn’t always obvious. Sometimes, it starts with a faint drip, a musty smell, or a puddle where it doesn’t belong. The longer it goes unnoticed, the more damage it can cause both internally and externally.
Why Your AC Might Be Leaking Water Indoors
When your air conditioner starts dripping water inside the house, it usually points to a clog, crack, or backup somewhere in the drainage system. That water isn’t coming from outside; it’s condensation. When warm air in your home moves over the chilly evaporator coil, the moisture in the air condenses into liquid. That water should drain into a pan, then flow out of the home through a small pipe. If any part of that process fails, water builds up.
Sometimes, the pipe gets blocked with algae, dust, or even insulation that has fallen into the drain. When the water has nowhere to go, it spills over the edge of the pan. That’s when you notice the damage. You might see ceiling stains or bubbling paint or hear a slow drip behind a wall. If your AC runs often, the water doesn’t stop, and the damage adds up. Fixing the leak means figuring out where the drain is failing, not just cleaning up the puddle.
How Frozen Coils Cause Water Leaks
One of the more surprising reasons for AC leaks is a frozen evaporator coil. It sounds like something that should cool better, not cause problems. But when that coil freezes, it starts a chain reaction. First, ice builds up around the copper tubing. That blocks airflow and insulates the coil, which means even more freezing. Eventually, the system shuts off or thaws suddenly.
When that happens, the ice melts all at once. Water spills down into the drain pan, and this can happen too quickly. If the drain is slightly blocked or the pan is small, the sudden rush of meltwater spills over the edge. That’s how you end up with water pouring out of the unit and onto the floor.
Coils freeze for a few reasons. You might have a dirty air filter that restricts airflow. You might be low on refrigerant, which drops the coil’s temperature too far. Either way, if you see ice on the coil or notice water leaking after your AC turns off, you’ve probably got a freeze-thaw problem on your hands.
What Happens When the Drain Pan Itself Cracks
Older systems can develop cracks in the drain pan, especially if the plastic starts to wear down or warp. Even metal pans can corrode or rust through, especially in coastal areas or homes with long cooling seasons. When that pan no longer holds water, it leaks every time the system runs.
Because the pan sits under the evaporator coil, it’s hard to see without opening the unit. You may spot a leak near the air handler but not be able to find its source. If the pan has a hairline crack, the leak might only appear during long cooling cycles.
Replacing the pan requires opening up the system and sometimes detaching parts of the coil housing. It’s not a small job, but it beats repairing ceiling damage or replacing drywall. If your system is more than 10 years old and leaks have started without any clear clog, a cracked pan is worth investigating.
How to Tell if Refrigerant Is Leaking Instead
Not all AC leaks are water. In some cases, the system might be losing refrigerant, which leads to other symptoms. You might notice a hissing or bubbling sound near the outdoor unit, or find that the AC runs constantly without cooling the house. In severe cases, the coil inside the unit can freeze over, which leads to water leaks when it melts.
Refrigerant leaks are a different category of problem. They often come from tiny pinholes in the coil or weak solder joints. Once the pressure drops, the system loses efficiency and cools unevenly. If left alone, it can damage the compressor or shorten the life of the entire system.
To find this kind of leak, HVAC techs use special tools to detect escaping refrigerant. They may also look for oil spots near connections, which indicate that refrigerant has escaped. If your AC is leaking but doesn’t show signs of water pooling, it might be time to check for something else leaking behind the scenes.
Why AC Leaks Can Happen After You’ve Made Changes
You might think an AC leak would only start if the system is old or neglected. But, sometimes, leaks show up after renovations or changes to your HVAC system. Maybe you added a new thermostat, expanded the ductwork, or upgraded the filter. Any of those changes can shift how the system handles airflow and condensation.
For example, a higher-rated filter that restricts too much airflow can cool the coil too fast, triggering freeze-ups. Or the slope of the drain line was accidentally changed during an attic project, making it harder for water to flow downhill. Even something simple like moving boxes around in a closet that houses your air handler can block airflow or press against the drain pipe.
If you’ve recently had work done and noticed puddles or strange sounds afterward, the leak might not be wear and tear. It could be a result of something new not playing well with the system’s original setup. That’s why it helps to mention all recent changes when diagnosing a leak.
When It’s Time to Shut Off the AC and Call for Help
There’s a difference between a system that drips a few drops during startup and one that floods your floor or leaves brown spots on the ceiling. If you’re mopping up daily or running fans to dry things out, the problem’s beyond DIY territory.
In most cases, it’s smart to shut the system off completely if you see steady leaking. That protects the wiring and the blower motor from water damage. Once the system is off, you can check the filter, the drain line, and the surrounding area for visible problems. If nothing obvious stands out, it’s time for a deeper inspection.
Waiting too long can lead to mold, warped wood, or insulation damage in the attic or behind walls. Leaks tend to travel, so the spot you see might not be the source. A trained tech can track it back, check airflow and refrigerant levels, and tell you if it’s a small repair or part of a larger issue. Once that’s fixed, the leak usually stops for good.
Let Us Handle Your AC Leak
Water damage from a leaking AC can sneak up fast, especially when it hides behind walls or builds up slowly in your attic. Acting early makes AC repairs easier and less expensive. We also handle drain line clogs, AC tune-ups, and full system checks. Call Polar Air & Heating, Inc. in Las Vegas, NV, today, if you need AC repairs to stop the leak.
