The Thermostat: The Brain’s of Your Heating and Air System

You might have a temperature control on a wall in your home to control the heating system but, although it's probably marked in degrees, it's not a thermometer. It's called a thermostat, a modern word based on two ancient Greek ones: thermo (meaning heat) and statos (which means standing and is related to words like stasis, status quo, and static—meaning to stay the same). We can tell just from its name that a thermostat is something that "keeps heat the same": when our home is too cold, the thermostat switches on the heating so things quickly warm up; once the temperature reaches the level we've set, the thermostat switches the heating off so we don't boil.

Let's just be clear about the difference: a thermometer is something that measures the temperature; a thermostat is something that tries to maintain the temperature (keep it roughly the same).

If you have specific heating and cooling needs in order to be comfortable then you've probably spent a little time looking at and operating your home thermostat. This handy little device controls the heating and air-conditioning systems in your house -- the two pieces of equipment that use the most energy, and the ones that have the biggest impact on your comfort and quality of life. In these days of rising energy prices, you might be interested to see how your thermostat works. Believe it or not, it's surprisingly simple and contains some pretty cool technology.

In this article, we'll take apart a household thermostat and learn how it works. We'll also learn a little about digital thermostats, talking thermostats, telephone thermostats and system zoning.