Condensation Taken From the Air
Some dehumidifiers are shaped like a box with a bucket inside it. This bucket is where the water collects when it is pulled from the air by force of suction. The air is heated and blown over very cold metal tubes or coils. Condensation forms on the coils, and when it builds up enough, it drips into the bucket that comes with the machine. Then the cooled air is warmed again before being released back into the room again. Quite often the returning air will actually be slightly warmer than it was when it entered the machine.
Some dehumidifiers actually have the capacity to drain the water from their own buckets through a hose connected to the water drain, which can be pumped electrically or through gravity by raising the dehumidifier higher than the water drain. Most machines will work in virtually any temperature, as long as it is not too extremely hot or cold. Most dehumidifiers are also equipped with sensors that determine when the water container is full and are programmed to automatically shut off.
Too Dry Is Not Good
Small dehumidifiers are good for smaller sized rooms and larger ones will cover a larger room area. Even the smallest machines, however, can be used for larger spaces, simply by periodically moving the device to another section of the house for a while. Try not to allow the machine to suck too much moisture out of the air, however, as this can result in a build up of static electricity and also cause dry skin. Most dehumidifiers have a digital readout that can be set to a particular percentage and will stop working when that humidity point is reached.