The reason heating thermostats have anticipators is to:

Heating thermostats are designed to control the temperature in a space by turning the heating system on and off as needed. Anticipators are components added to thermostats to improve their performance in maintaining the desired temperature more accurately. The primary function of anticipators is to reduce overshoot, which is when the temperature surpasses the set point before the system shuts off.

When a heating system turns on, there is usually a delay in the actual temperature response due to thermal inertia in the building materials and the heating system itself. This delay can cause the heating system to continue operating even after the desired temperature is reached, leading to an uncomfortable over-temperature condition. By using an anticipator, the thermostat can predict this lag and turn off the heating system a little earlier than it normally would, preventing the temperature from exceeding the set point significantly.

This predictive capability allows for a more stable and controlled heating environment, enhancing comfort and energy efficiency. Thus, the inclusion of anticipators in thermostats is a key feature aimed at improving temperature regulation by minimizing overshoot.