On thermostats that automatically control both heating and cooling systems, a deadband is a temperature range in which neither system turns on. The deadband prevents the thermostat from activating heat and cooling in rapid succession. This conserves energy by providing a range of temperatures requiring no energy consumption.

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Thermostats that control both air conditioning and heating have deadbands.

Presence of the Deadband

Older dial thermostats that control only the furnace do not have a deadband. Nor do thermostats with manual switches to activate either heating or cooling. Deadbands are present on newer thermostats that automatically switch between heating and cooling.

Control of the Deadband

The deadband is designed to keep heating and cooling systems from running at the same time. You set your thermostat to trigger heating at a much lower temperature than what you would set it at for cooling. For example, a temperature of 75 degrees may trigger the cooling system, while the heater may turn on at 68 degrees. In that case, the deadband is from 68 to 75 degrees.

Programmable Thermostats

Digital programmable thermostats are available in a variety of styles and types. Some have factory pre-set deadband zones. The common deadband zone is a 3- to 6-degree zone that acts as a neutral zone where no activity takes place. Both systems remain idle until the temperature either rises above or falls below the zone.

Comfort Issues

If you have elderly or invalid persons living with you, a deadband may cause them to feel chilly or too warm. The region in which you live also has a bearing on the comfort of the infirm or elderly. This is something to consider when purchasing a new heating/cooling system and thermostat.