A thermostat has a temperature sensor and an activating switch. Some are mechanical, others electronic. Not all thermostats work with all types of furnaces and heaters; a forced-air thermostat, for example, won't necessarily work with a heat pump. Most thermostats are either manual, electronic or "line-voltage" (used with electric baseboard and wall mounted heating).

Programmable, electronic thermostats couple sensors with circuitry to do the job. Typical programmable thermostats can handle both heat-only systems-such as forced-air, steam, hot water, and, in some cases electric-and complete air-conditioning systems. Most are like minicomputers that can automatically align heating and cooling to changing daily needs, eliminating unnecessary energy usage and reducing energy costs.

Not all thermostats work with all types of furnaces and heaters; a forced-air thermostat, for example, won't necessarily work with a heat pump.

Most thermostats are either manual, electronic or "line-voltage" (used with electric baseboard and wall mounted heating).

Programmable, electronic thermostats couple sensors with circuitry to do the job. They require little maintenance.

-- Tips courtesy of HomeAdvisor.com