Traditional heating and cooling equipment is either on or off. Not only does it require significant energy to turn on, it can only function at full capacity, even when warming up the house by just a few degrees. A more efficient option for heating is a dual-speed or two-stage heating and cooling system that has two levels of output - high for colder or hotter periods and low for milder periods. Since the low setting is adequate most of the time, the two-stage unit can operate on low for longer periods to provide more even heat distribution at greater efficiency.