What is a Line Voltage Thermostat?

A line voltage thermostat is commonly used to control electric baseboard heaters or a direct-wired electric furnace. It works by turning on the power to the heating and cooling system when the thermostat detects the room temperature is no longer within a few degrees of the desired setting. The power supply, measured in volts, is switched directly on and off by the thermostat.

Thicker power wires are an identifying characteristic of a line voltage thermostat. It operates using a direct current of power and is typically seen in older buildings. Programmable, digital and non-digital thermostats are compatible with a line voltage system.

Some types of thermostats are designed for use with a particular range of line voltage systems. For example, a certain thermostat model may not be designed to work with a central heating and cooling system. Instead, it may be designed to work exclusively with electric baseboards or a floor heating system.

A programmable line voltage thermostat features the ability to automatically adjust temperature settings according to day and time. In the winter months, a lower temperature might be set at night or during the day when a home is not in use. Likewise, a higher temperature might be set during the hours of the day when the home is in use and increased comfort levels are desired.

Some of the features of a non-programmable line voltage thermostat include either a digital or traditional dial control. With the dial control, a user manually adjusts the temperature setting. In order to ensure that the heating or cooling system does not activate, the temperature might need to be set at a certain minimum or maximum threshold.

Thermostats might include a soundproof feature, which helps reduce the clicking noise that is commonly heard when line voltage systems are switched on. Some thermostats have the ability to detect room temperature within one degree of accuracy, which offers the benefit of better temperature control. Provided that it is mounted away from direct sunlight, drafts or closed off spaces that might interfere with its ability to sense actual temperature, a thermostat helps reduce energy costs by increasing the system's efficiency.

It is recommended that the installation of a line voltage thermostat be performed by a certified electrician. Power to the heating or cooling system should be shut off during the installation in order to avoid electrical shock. While some models will feature a two-wire configuration, others might feature a four-wire. Line voltage thermostats are typically installed onto electrical boxes by connecting the thermostat wires to the power and load connectors.