A heat-only thermostat is a temperature-regulating device that is compatible with a single heating source only. It is generally used with a baseboard heating system or a forced hot air unit. A heat-only thermostat is not compatible with cooling systems, such as air-conditioning units.
Heat-only thermostats are available in programmable or nonprogrammable models. A programmable heat-only thermostat allows the user to set different temperatures during different times of the day. Some programmable models have settings for morning, daytime, evening and overnight. Other programmable thermostats allow temperatures to be programmed at specific times during the day. Programmable heat-only thermostats typically use a digital screen interface, while nonprogrammable thermostats use a rotating dial or sliding lever.