Vented dryers take in air from inside the room, heat it up and tumble it through your clothes, and then pushes the hot, wet air outside through a duct. Because of this design, vented dryers needs to be placed near a window or an external wall so that the air can escape out the duct. Vented dryers are generally more affordable to buy and ideal for a smaller household.
Condenser dryers use a heat exchanger to remove moisture from the warm air that has heated your clothes. The water is stored in a tank or drained away and the heat is pumped back into the room where the dryer is. Some newer models have a sensor function which detects how long you clothes need to dry for and when to stop. Condenser dryers do not need an external duct so can be placed anywhere and are ideal for larger households.
Heat pump dryers work in a closed loop - air is heated and tumbled through the clothes, and then cooled with the water drained off, and then reheated again to go back through the clothes. No moisture is released into the air. They are most energy efficient dryer and like the condenser dryer they do not need an external duct so can be placed anywhere. Heat pump dryers are ideal for larger households who want to cut down on their bills.