But in fact, the central plains and east area of many places, winter temperatures fall below zero degrees Celsius time more than a month, these areas also have great heating demand.

Six of the ten most virtuous metropolitan areas are on the west coast, where Pacific breezes lessen demand for heating and air-conditioning.

A cold snap in the winter of 2005-06 led to a spike in demand for natural gas, which is used both as a heating fuel and to generate electricity.