A heat anticipator is used in an electromechanical heating thermostat to ______.

• A. Increase the furnace firing rate
• B. Shut down the furnace shortly before the thermostat setpoint would otherwise be satisfied
• C. Delay the thermostat response
• D. Shorten the furnace runtime by a fixed amount each cycle

Answer: (B)

Heat anticipators bias the thermostat’s sensing element so the switch opens slightly before the room actually reaches the setpoint. In an electromechanical thermostat, a small amount of heat is added to the sensing area, warming the bimetal strip just enough to reach the off point sooner. The result is the furnace shuts down shortly before the thermostat setpoint would otherwise be satisfied, compensating for the lag between turning the furnace on/off and the room temperature rise. This helps reduce overshoot and short cycling. It doesn’t increase firing rate, delay the response, or shave a fixed amount of time off each cycle—the effect is a small, adjustable bias to match the system’s real-world behavior.