What is a deadband in thermostat control?

• A. The temperature range around the setpoint where control action is intensified.
• B. The temperature range outside which the system cannot operate.
• C. The temperature range around the setpoint where no control action occurs; it reduces cycling and equipment wear.
• D. The temperature range within which the thermostat actively heats only.

Answer: (C)

A deadband is the temperature range around the setpoint in which the thermostat does not take any action. This gap prevents the heating or cooling system from cycling on and off as the room temperature fluctuates near the target. For example, if the setpoint is 72°F and the deadband is 2°F, heating will not start until the temperature falls to 70°F and cooling will not start until it rises to 74°F. Once the temperature moves back toward the setpoint and enters the deadband, the system turns off, reducing wear and energy usage. This behavior is not about intensified action, nor about an exclusive operating limit or a zone where heating is always active; it’s the neutral band that keeps the system from constantly cycling.