How do I stop my window air conditioner from spitting up water?

If your window air conditioner is spitting water into your room, it can be annoying and cause damage. The good news is that in most cases, this issue can be fixed with some simple adjustments or maintenance.

What Causes a Window AC to Spit Water?

There are a few common causes of a window air conditioner spitting water:

• The AC is not level – If the back of the AC is lower than the front, water can build up and spill over the edges.
• The drain holes are clogged – Most ACs have a drain hole or drain hose to remove condensed water. If this gets clogged, water can back up and spill into the room.
• The cooling coils have frost buildup – Ice on the coils can melt and run into the room. This is common if the AC is set too cold.
• High indoor humidity – If the indoor air is very humid, more water will condense on the AC coils and can spill over.

How to Fix a Window AC Spitting Water

Here are some step-by-step solutions to try if your window AC is spitting water into the room:

1. Make Sure the AC is Level

For the AC drain to work properly, the unit needs to be slightly tilted so water can run out the back or side drain holes. Use a bubble level to check that the back of the AC is slightly lower than the front. Shim the base pan if needed to get it perfectly level.

2. Clean the Drain Holes

Clogged drain holes are a very common cause of water spitting issues. Locate the primary drain hole along the bottom or side of the AC. This may have a plastic drain spout or just be an open hole. Use a stiff wire or pipe cleaner to clear any dirt, algae, or debris clogging the drain. Flush with water to ensure it’s fully clear.

3. Adjust the Slope of the Drain Hose

If your AC has a drain hose rather than just an open drain hole, make sure the hose is properly positioned. It should slope downward so water can easily run out. Kinks in the hose can obstruct drainage and cause water to back up.

4. Remove Excess Frost from the Coils

If ice builds up on the AC’s evaporator coils, the melting water has to go somewhere – usually into your room. Excess frost is a sign the AC is set too cold for the humidity level. Try turning the temperature up slightly to allow the ice to melt. Once it’s melted, you can resume normal settings.

5. Adjust the Air Conditioner’s Slope

For optimum drainage, most window AC units should have a slight downward tilt of between 3 and 4 degrees. To adjust the tilt, loosen the bracket screws and reposition the unit. Use a bubble level across the top of the AC to achieve the right slope before tightening the bracket again.

6. Insulate the Drain Hose

If the drain hose or spout feel cool to the touch, the water condensing on them can obstruct drainage. Slide some foam pipe insulation over the drain and several inches up the back of the AC to prevent this.

7. Install a Drain Hose Extension

Extending the drain hose helps water flow out of the AC unit more easily. Attach an additional 1-2 feet of hose onto the existing drain. Make sure the extension slopes down and away from the window. Secure it with wire, clamps or ties.

8. Check the Air Filter

A dirty air filter can block airflow and reduce the AC’s cooling power. This can cause excess frost and water buildup. Unclip the filter and rinse or replace it if it’s covered in dust and dirt.

9. Raise the Temperature Setting

If the AC unit is set very low on a hot, humid day, the temperature difference can cause a lot of condensation on the coils. Try turning the temperature up 2-3 degrees to reduce frost buildup.

10. Lower the Indoor Humidity Level

Using a dehumidifier or turning on exhaust fans when showering or cooking can lower indoor humidity. Less moisture in the air results in less water condensing on the AC, reducing spitting issues.

When to Call a Professional

If you’ve tried these troubleshooting tips and your window AC is still spitting water, it likely needs servicing by an HVAC technician. A pro can test the refrigerant levels, check for leaks, clear clogs, and confirm the drain pan is draining properly. Replacement of the unit may be needed if it’s too old or damaged. Calling a professional prevents water damage and ensures your AC is working efficiently.

Tips to Prevent Water Spitting Problems

With some preventive maintenance, you can avoid many water spitting issues:

• Clean the filter every 1-2 months of use.
• Vacuum the front intake grilles a few times per year.
• Clear debris from the drain holes with pipe cleaners.
• Place a pan under the unit to catch drips.
• Avoid very cold settings below 70°F on humid days.
• Angle curtains above the AC to prevent condensation.
• Run a dehumidifier in very humid rooms.

Conclusion

A window air conditioner that drips or spits water into a room can be very frustrating. In many cases, the problem is due to clogged drain holes, incorrect slope or level, or very cold settings in humid weather. Trying the troubleshooting tips above should resolve most water spitting issues. If the problem persists, call in an HVAC technician to service your AC unit. With routine care and cleaning, you can prevent water drainage problems and keep cool all summer long.