Running cold water does not release humidity from the room; in fact, it can potentially add humidity to the room if the water is left to evaporate. The process of evaporation involves water changing from a liquid to a vapor state, and this adds moisture to the air, increasing humidity.
On the other hand, turning on an air conditioner can effectively reduce humidity in a room. Air conditioners work by cooling the air and removing moisture from it through condensation. When warm air passes over the cooling coils of the air conditioner, the moisture in the air condenses into water droplets, which are then drained outside. This process reduces the humidity level in the room, creating a more comfortable and cooler environment.
So, if you want to lower the humidity in a room, it's better to rely on the air conditioner rather than running cold water. However, if you are trying to increase humidity in a dry room, you can use methods like using a humidifier or placing containers of water to allow for natural evaporation.