If you suspect that your dryer is not as efficient as it used to be you need to be checking a series of non mechanical problems.
We recommend the following:
Ensure that the vent hose is not blocked or crushed.
Ensure that the lint filter is clear from fluff build up.
If your dryer has a water container, ensure it is empty.
Ensure that your dryer is not being overfilled with clothing as this will impair the performance.
Double check the heat switch on your dryer is set to the appropriate position.
Ensure that the condenser unit has been washed using running water.