Why is the typical low voltage for a gas furnace 24 volts?

The typical low voltage for a gas furnace is 24 volts because it provides a safe and efficient operating level for the control circuitry and components, such as thermostats and relays. This voltage is low enough to minimize the risk of electric shock while ensuring sufficient power to operate the furnace's ignition system and safety controls. Additionally, 24 volts is a standard used in HVAC systems, allowing for compatibility and ease of integration with various components across different manufacturers.