We have a Zanussi washer/dryer WJS 1265 W which is not drying as well as it did when new (it's now about three years old). It takes two goes to get stuff dry, ie one go of 2.31min and one of 1.39min. We are not overloading the machine - eg one bath sheet and one hand towel dry weight only 2 1/4 lbs (5 Kg). The filter is clear. The spinner seems to work OK. There seems to be suspiciously little electricity consumption when the machine is drying. (The electric meter seems to move no more quickly than when the machine's not drying).
What, do you think, is the likely reason for this? What are the mechanics of the drying function? Where does the heat come from in the drying process? Is there a fan or blower of some kind?