Hot plates that use induction burners that heat with magnetic coils are the most energy-efficient. Conventional electric hot plates spend most of their energy to heat the burner surface, whereas induction models transfer the majority of their heat energy directly to the pan.
Induction models also cook faster. In a Consumer Reports test, induction burners brought 1.5 gallons of water to a boil in about half the time that it took conventional hot plates to boil the same volume of water. Induction models usually cost significantly more than their conventional counterparts. Portable induction cooktops made by Nesco and Aroma are available at Best Buy, Target and Amazon.com.