Designed for low volt systems. Developed with convenience and comfort in mind. Low volt requires higher expectations with thermostats. Most won't do. That's why we make our Digital Non-Programmable Thermostat RTH111B1024. It's designed for low volt heating and cooling systems, including millivolt and single-stage heat pumps without auxiliary heat. It also has convenient features such as an easy-to-read display and easy-access battery replacement, as well as a singular focus on your comfort with our precise comfort control.