The next step up is a remote line-voltage thermostat, which is typically associated with electric wall and baseboard heaters. Since they are installed on a wall as opposed to directly on the heater, and also have more sensitive controls for setting temperature, they tend to be both easier to set and more accurate. Some types of line-voltage thermostats are also capable of timer settings, which allow the thermostat to automatically raise and lower the temperature of the heater at selected times of day.

Low-voltage thermostats are the standard for all types of central heating and cooling systems, as well as for such devices as pellet stoves and gas fireplaces. Low-voltage thermostats are centrally located in the area where accurate sensing of temperature is most important, typically the living room or a central hallway. Low-voltage thermostats are connected to the furnace unit with small-gauge wiring, which also simplifies installation.

Low-voltage thermostats range from ones with simple mechanical controls, limited features, and fair to good accuracy, up to ones with electronic controls, dozens of available settings, and the ability to read and adjust temperatures with great accuracy. Whether you are having a new furnace installed or are simply considering an upgraded thermostat for your existing system, you'll find a number of available choices.

For greatest convenience and energy savings, electronic automatic-setback thermostats are a good choice. Setback thermostats utilize a digital display for the setting and monitoring of desired heating and cooling temperatures, as well as a number of push-button controls for inputting commands. Many are suitable for do-it-yourself installation utilizing existing low-voltage wiring, and in addition to the convenience, you will often find that the automatic accuracy of the thermostat will help it pay for itself in energy savings.

The typical setback thermostat offers four control settings that allow you to set different temperatures for different times of the day. The "wake" setting is for the temperature you want to have the house reach before you wake up in the morning; the "leave" setting sets the temperature back when you leave for work and the house is unoccupied; "return" raises the temperature back up prior to your arrival home in the evening; and "sleep" lowers the temperature back down for when you go to bed. If your system has cooling capabilities, switching the thermostat to the cooling mode will offer you the same four setting options for the air conditioning side of the system.

Some setback thermostats offer individualized settings for "weekdays" and "weekends," and the better ones allow you to make different settings for each individual day of the week. Programming the thermostat is simple, and typically requires only about 15 to 20 minutes when the thermostat is first installed. Battery backups hold the program in memory in the event of a power outage.

Additional control buttons allow you to override the program and raise or lower the temperature temporarily or to hold a different temperature for as long as you want, all without altering the stored program. This is a real advantage if you want to warm the house up a little more on a cold day, or if you want to temporarily hold a lower temperature while you're away on vacation.