The old tumble drier is past its use-by date and it is time to get a new one. The old one vents through a pipe to the outside and the new one will be a condensing type. I really can't think that they are efficient devices (efficiency in the loose sense, of course) as they seem to use the incoming, room temperature, air to cool the outgoing air in a heat exchanger and the condensate is collected in a tank. There are now 'heat pump' versions available, which I guess, use a refrigeration unit to increase the temperature difference, and drying the inlet air etc. etc. Does anyone have experience of the new types and are they worth the extra £100+? The refrigeration unit is just one more thing to go wrong, of course but they do tend to run and run in other devices.