• Energy & Power

Thermostats with Automatic Temperature Adjustment

To maximize your without sacrificing comfort, you can install an automatic setback or programmable thermostat. They adjust the setting for you. While you might forget to turn down the before you leave for work in the morning, a programmable thermostat won’t! By maintaining the highest or lowest required temperatures for four or five hours a day instead of 24 hours, a programmable thermostat can pay for itself in energy saved within four years.

have features with which you may be unfamiliar. The newest generation of residential thermostat technologies is based on microprocessors and thermistor sensors. Most of these perform one or more of the following energy control functions:

  • They store and repeat multiple daily settings, which you can manually override without affecting the rest of the daily or weekly program.
  • They store six or more temperature settings a day.
  • They adjust heating or air conditioning turn-on times as the outside temperature changes.

Most programmable have liquid crystal temperature displays. Some have back-up battery packs that eliminate the need to reprogram the time or clock in case of a power failure. New programmable can be programmed to accommodate life style and control as needed.

Types of Automatic and Programmable Thermostats

There are five basic types of automatic and programmable thermostats:

  • electromechanical
  • digital
  • hybrid
  • occupancy
  • light sensing

Most range in price from $30 to $100, except for occupancy and light sensing thermostats, which cost around $200.

Electromechanical thermostat

Electromechanical (EM) thermostats, usually the easiest devices to operate, typically have manual controls such as movable tabs to set a rotary timer and sliding levers for night and day temperature settings. These thermostats work with most conventional heating and cooling systems, except heat pumps. EM controls have limited flexibility and can store only the same settings for each day, although at least one manufacturer has a model with separate settings for each day of the week. EM thermostats are best suited for people with regular schedules.

digital thermostat

Digital thermostats are identified by their LED or LCD digital readout and data entry pads or buttons. They offer the widest range of features and flexibility, and digital thermostats can be used with most heating and cooling systems. They provide precise temperature control, and they permit custom scheduling. Programming some models can be fairly complicated; make sure you are comfortable with the functions and operation of the thermostat you choose. Remember, you won’t save energy if you don’t set the controls or you set them incorrectly.

Hybrid systems combine the technology of digital controls with manual slides and
knobs to simplify use and maintain flexibility. Hybrid models are available for
most systems, including heat pumps.

Occupancy thermostats maintain the set back temperature until someone presses a button to call for heating or cooling. They do not rely on the time of day. The ensuing preset “comfort period” lasts from 30 minutes to 12 hours, depending on how you’ve set the thermostat. Then, the temperature returns to the setback level. These units offer the ultimate in simplicity, but lack flexibility. Occupancy thermostats are best suited for spaces that remain unoccupied for long periods of time.

Light sensing heat thermostats rely on the lighting level preset by the owner to activate heating systems. When lighting is reduced, a photocell inside the thermostat senses unoccupied conditions and allows space temperatures to fall 10° below the occupied temperature setting. When light ing levels increase to normal, temperatures automatically adjust to comfort conditions. These units do not require batteries or programming and reset them selves after power failures. Light sensing thermostats are designed primarily for stores and offices where occupancy determines lighting requirements, and therefore heating requirements.