Window air conditioners are designed to be used with clean, potable water. The only type of water you should put in a window air conditioner is regular tap water or distilled water.
It's important to avoid using any other types of water, such as saltwater, mineral water, or water from non-potable sources (e.g., lakes, ponds, rivers), as they may contain impurities or minerals that can harm the air conditioner's components. Additionally, using water with high mineral content can lead to mineral buildup, which can negatively impact the unit's efficiency and performance over time.
If your window air conditioner has a water reservoir or requires periodic water filling for its cooling function (as seen in some evaporative coolers or portable air conditioners), always follow the manufacturer's guidelines and use clean tap water or distilled water as specified in the user manual. Regular maintenance and using the correct type of water will help ensure the efficient and safe operation of the air conditioner.