A:Answer A heating element uses a lot of electricity. With tightening federal energy standards, most manufacturers have ditched the heating element in favor of a condensation drying system. These systems use a heated rinse at the end of a cycle to coat dishes in hot water. The cool, stainless-steel interior walls of the dishwasher then draw the hot water off of dishes and channel it into the drain. Condensation drying works fine for most glasses and porcelain, but even manufacturers will admit that plastics may not get completely dry.
Taken from: http://dishwashers.reviewed.com/features/why-doesnt-my-dishwasher-dry-dishes
I have never used the active drying element on my old dishwasher. Never. Certainly the plastics are not quite dry at the end of the cycle; then it's maybe another 10-15 minutes afterwards with the top rack pulled out half way and the door partially open to complete the drying process. No big deal. Better for the environment, better for your wallet.