Why is My Air Conditioner Leaking Water Inside?
Discovering a puddle of water pooling around your indoor furnace or air handler is a surefire way to ruin your day. Not only does it indicate that your HVAC system is malfunctioning, but it also poses a serious threat to your home's drywall, flooring, and structural integrity.
While air conditioners are designed to handle water, that water is supposed to be safely routed outside. When it ends up on your basement or utility closet floor, it’s time to investigate. Let's break down why your AC creates water in the first place, and what causes it to leak indoors.
Why Does an AC Produce Water?
Your air conditioner does more than just cool the air; it also dehumidifies it. As warm, humid indoor air is blown across the freezing cold evaporator coil, the moisture in the air condenses into water droplets—exactly like the condensation on the outside of a cold glass of sweet tea on a hot summer day.
These water droplets drip off the coil and fall into a drain pan located beneath the unit. From there, the water flows down a PVC pipe (the condensate drain line) and safely exits your home. On a highly humid day in Kentucky, a standard AC can produce anywhere from 5 to 20 gallons of water a day. When the drainage system fails, that water ends up on your floor.
The Top Causes of Indoor Water Leaks
1. A Clogged Condensate Drain Line
This is by far the most common cause of a leaking air conditioner. The condensate drain line is cold, dark, and constantly damp—the absolute perfect breeding ground for algae, mold, and mildew. Over time, this biological growth clumps together and forms a severe clog inside the PVC pipe.
When the pipe is blocked, the water backs up into the drain pan. Once the pan is full, it overflows directly into your home. A wet/dry shop vac can often clear the clog if applied to the outside exit pipe.
2. A Rusted or Cracked Drain Pan
If your HVAC system is older (typically 12 to 15+ years), the drain pan beneath the evaporator coil may have deteriorated. Older systems used metal pans that eventually rust through. Modern systems use heavy-duty plastics, but these can become brittle and crack over a decade of temperature fluctuations. If the pan is compromised, water will drip straight through it.
3. A Frozen Evaporator Coil
If your AC system freezes up due to a dirty air filter or low refrigerant, a massive block of ice forms on the indoor coil. Eventually, that ice has to melt. When it melts rapidly, the sheer volume of water can quickly overwhelm the capacity of the drain pan and the drain line, causing it to spill over.
4. Disconnected or Improperly Pitched Drain Lines
Sometimes, the PVC drain line gets accidentally bumped or kicked, causing a joint to disconnect. Additionally, if the pipe was not installed with the correct downward pitch (gravity slope), water will pool inside the pipe rather than flowing outside, eventually backing up into the system.
How to Prevent Water Damage
If you see water pooling around your system, immediately turn the thermostat to "Off" to stop the production of condensation. Clean up the water to protect your floors, and call Ironclad Comfort Solutions. We can clear severe clogs, repair damaged pans, and install safety float switches that automatically shut off the system if water begins to back up.
Frequently Asked Questions
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