Which device is primarily used for measuring temperature in a heating system?

In a heating system, the primary device for measuring temperature is the thermostat. A thermostat is specifically designed to maintain a desired temperature within a particular space by controlling the heating system accordingly. It can sense the current temperature and compare it to the set temperature, sending signals to the heating system to either turn on or off to maintain the desired level.

While other devices, like sensors, can also measure temperature, their application is often broader and not limited solely to controlling heating systems. Manometers measure pressure, not temperature, and transmitters can send temperature data but do not inherently measure temperature in the same direct manner as a thermostat does. This makes the thermostat the most appropriate choice for the primary function of measuring temperature in heating systems.