Dehumidifiers work by pulling moisture from the air, reheating the air and releasing the dry air back into the room. These machines operate as a result of condensation, which takes place when air is cooled and heat is released in the process.
Dehumidifiers use a fan compressor with a refrigerant such as Freon to cool the coils on the machine. Condensation on the coils helps to collect moisture from the surrounding air, which drips into the dehumidifier’s water reservoir. This works because air loses its ability to retain moisture as it loses heat. The cooler surface of the cooling coils pulls moisture out of the air as it comes in contact with the cold coils. The machine also has a reheater that captures the heat generated by the cooling process, drying the air and exhausting the drier air back out to the room.
All humidifiers must drain the water collected. Most have a bucket that acts as a reservoir and can be removed to dump the water. Dehumidifiers typically have an automatic shut-off so the reservoir won’t overflow. Many also have a hose hook-up, allowing the water to drain out into a pump or floor drain via gravity. For more heavy-duty needs, there are dehumidifiers with a built-in pump to continually pump out the collected water.