If your window air conditioner is dripping water into the room instead of draining outside, it's almost always an installation tilt or clogged dra in issue. We cover the 6 most common causes and how to
Work through these in order, the most common causes come first.
Nearly every window air conditioner needs to sit tilted slightly downward toward the outside, generally a quarter to half inch lower on the outdoor side than the indoor side.
This small angle is what lets gravity carry condensation to the dra in holes and out of the unit rather than pooling on the indoor side.
Use a level placed on top of the unit to check the current angle.
If it's level or tilted the wrong way, adjust the mounting rail, shims, or foam blocks underneath until the outside edge sits slightly lower.
Water drips steadily from the bottom of the indoor side: most likely an installation tilt problem.
Recheck and correct the angle first.
Water appears only after the unit has been running for hours on a very humid day: likely a temporary condensation overload rather than a mechanical fault.
Monitor whether it resolves as outdoor humidity drops.
Water appears mainly when the unit is turned off or the compressor cycles down: often ice that built up on the coil during operation, now melting faster than the dra in system handles.
Our picks
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Frigidaire
Frigidaire's slider/casement AC is shaped tall and narrow to fit windows that open sideways.
GE Profile
8,300 BTU edges out the 8,000 BTU competitors here for genuinely large 300 to 350 sq ft rooms
Midea
Inverter compressor uses less energy than a fixed-speed unit when it's running most of the day, which matters in a room people occupy from morning to night
FAQ
The most common cause is an installation tilt problem. Window units are designed to sit tilted slightly downward toward the outside, typically about a quarter to half inch lower on the outdoor side, so condensation drains outward rather than pooling and dripping back into the room. If the unit is level or tilted the wrong way, water collects on the indoor side and leaks in.
Yes, this is normal and expected. Window units remove humidity from the room as part of the cooling process, and that moisture has to go somewhere. A properly installed unit drains this condensation out the back or bottom to the outside; the problem is only when water appears inside the room, not outside.
A clogged filter restricts airflow across the evaporator coil, which can cause the coil to get too cold and ice over. When that ice later melts, usually when the compressor cycles off or the unit is turned off, it can produce more water than the dra in system is designed to handle at once, leading to an overflow inside.
It's worth turning it off and checking the installation tilt and dra in before continuing to run it, especially if water is reaching a windowsill, wall, or flooring that could be damaged. Most leaks are a straightforward installation or maintenance fix, not a sign the unit needs replacement.
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