Thomas & Galbraith offers programmable thermostat installation for your home heating and cooling system.
The days of manually "cranking" a thermostat up and down are over. An electronic programmable thermostat is now considered the key component for getting the most out of today's heating and cooling systems while reducing energy usage.
There are two basic types of thermostats - mechanical and digital (with variations of manual and programmable for each). The mechanical thermostat is the old style. Most of us haven't looked inside a thermostat control box, but if you do, you'll usually find a coil of metal (actually 2 metals, called bi-metallic) attached to a glass vial filled with liquid mercury. The old style thermostats use special metals with certain heat properties; the metal coil contracts and expands as the room temperature changes. As the metal moves, the pivoting glass vial on top of it will tilt to one side or the other, and the liquid mercury (another metal) will pool on one side or the other, connecting or disconnecting the electric circuit and causing the furnace or air conditioner to turn on or off. There is normally a temperature slider bar for setting the desired temperature which affects the position of the coil and contact points for that temperature.
Newer digital thermostats use thermistors (thermal resistors) to detect changes in temperature, and hence have no moving mechanical parts. The thermistor changes resistance as its temperature changes, so by connecting it to some chips and other electronics, the digital thermostat can easily detect the room temperature.
Most digital thermostats are powered by batteries, so you must remember to replace them each year. One big advantage over mechanical thermostats are the large, easy to read LCD screens that most digital thermostats offer. Instead of squinting and trying to read the graduated lines on a little bar, you can easily see the bright temperature displays on these newer models.
Programmable thermostats do two things: (1) Compare the thermometer reading of a room's temperature to the "ideal" thermostat temperature you select. (2) Give start-and-stop commands to the heating or cooling system in order to achieve an indoor temperature that is as close to your "ideal" thermostat setting as possible. By doing those two things, a thermostat plays the role of a "comfort detective" in your home.
The big advantage of a programmable thermostat is that you can program (or in other words…setback) multiple "ideal" temperatures for different times of the day or night, or for different days of the week.
Thermostat setback is simple: when you need heating or cooling, you program the thermostat to order your system to work achieving the ideal temperature. But when you don't need as much heating or cooling, you program the thermostat to "setback" the ideal temperature for awhile.
Another big advance is in programmable thermostats. Programmable thermostats offer you the energy saving advantage of turning themselves down automatically (thus keeping the furnace off for longer periods) at certain times of the day, like after midnight when everyone is in a warm bed, or during the middle of the day when the family is out at the office and school. They can be set for certain time periods you prefer (heat comes on at 6:30, 10 minutes before you get out of bed, for example) and for certain days of the week. Of course, you could manually make the same changes, turning the temperature down before bed, back up when you get up, down when you go to work, etc. but this can be a hassle and is often forgotten, leaving the furnace or AC chugging away when no one is home to appreciate it.
If you turn down the heat 1 degree for eight hours a day, you can save about 1 percent of your heating energy costs. Turn it down 10 degrees to save about 10 percent. The same goes with the air-conditioning: Turn the temperature up 10 degrees for eight hours a day to save approximately 10 percent on your bill.
And you can achieve the same kinds of savings with summer cooling setbacks when the house is empty during the day, or after you've fallen asleep in your cool, comfortable bedroom.
While programmed setbacks make the most measurable differences in energy costs, a programmable thermostat saves in other ways as well. Newer electronic thermostats are far more accurate than older, manual thermostats. An older thermostat could allow temperature variations of up to five degrees. New electronic thermostats can be accurate to within a half a degree. That means less wear and tear on your furnace and air conditioner from too much turning on and off.