Final answer:
The two main types of thermostats are low-voltage, common in central heating and cooling systems, and line-voltage, typically used with electric resistance heating systems like baseboard heaters.
Step-by-step explanation:
The two main types of thermostats are low-voltage and line-voltage. A low-voltage thermostat is typically used in central heating and cooling systems and operates at 24 volts. They are known for their versatility and can support programmable and smart functions. On the other hand, a line-voltage thermostat is typically used for electric resistance heating systems, like baseboard heaters, and operates at the same voltage level as the home, which is usually 120 volts or 240 volts.